Cutover engine based on synchronous replication

Abstract

Techniques for synchronous replication-based cutover are provided. An asynchronous replication process is executed to perform asynchronous incremental transfer of data of a storage object from a first computing environment to a replicated storage object at a second computing environment until cutover criteria are met. The synchronous replication process is executed based on the cutover criteria being met to synchronously replicate operations targeting the storage object to the replicated storage object. The cutover is performed based on the synchronous replication process reaching a stable state of synchronous replication for child objects of the storage object to direct operations from targeting the storage object to targeting the replicated storage object, wherein the operations are submitted to both the storage object and the replicated storage object.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. Patent Application No. 16 / 191,582, filed on November 15, 2018, and entitled “SYNCHRONOUS REPLICATION BASED CUTOVER ENGINE,” which claims priority to Indian Patent Application No. 201841029051, filed on August 2, 2018, and entitled “SYNCHRONOUS REPLICATION BASED CUTOVER ENGINE,” which applications are incorporated herein by reference. Background Art

[0003] Many storage systems can implement data replication and / or other redundant data access techniques for data loss protection and uninterrupted client access. For example, a first computing device can be configured to provide a client with primary access to data stored in a first storage device and / or other storage devices. In the event of a failure of the first computing device, a second computing device can be configured as a backup of the first computing device. Data can be replicated from the first computing device to the second computing device. In this way, in the event of a failure of the first computing device, the second computing device can provide the client with access to the replicated data.

[0004] Storage virtual machines can be used to manage storage (e.g., multiple volumes stored across one or more nodes of a cluster) and provide clients with access to such storage. It may be beneficial to migrate a storage virtual machine from one cluster to another, such as for load balancing. Unfortunately, migrating a storage virtual machine can be very disruptive to clients. This is because the client's access to the storage hosted by the storage virtual machine is quiesced (blocked), which increases client I / O latency and may cause applications that rely on data in the storage to time out or encounter errors, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] Figure 1 is a component block diagram illustrating an example cluster network in which embodiments of the present invention may be implemented.

[0006] Figure 2 is a component block diagram illustrating an example data storage system in which embodiments of the present invention may be implemented.

[0007] Figure 3 is a flow chart illustrating an example method for synchronous replication based cutover.

[0008] Figure 4Ais a component block diagram illustrating an example system for synchronous replication based cutover, wherein asynchronous replication is performed.

[0009] Figure 4B is a component block diagram illustrating an example system for synchronous replication based cutover, wherein synchronous replication is performed.

[0010] Figure 4C is a component block diagram illustrating an example system for synchronous replication based cutover, wherein a cutover phase is performed.

[0011] 4D is a component block diagram illustrating an example system for synchronous replication based cutover, in which client access is cutover to replicated storage objects.

[0012] Figure 5 is an example of a computer-readable medium in which embodiments of the present invention may be implemented.

[0013] Figure 6 is a component block diagram illustrating an example computing environment in which embodiments of the invention may be implemented. DETAILED DESCRIPTION

[0014] Some examples of the claimed subject matter are now described with reference to the accompanying drawings, wherein similar reference numerals are generally used throughout to refer to similar elements. In the following description, for the purpose of explanation, many specific details are set forth in order to provide an understanding of the claimed subject matter. However, it is clear that the claimed subject matter can be practiced without these specific details. Nothing in this detailed description should be considered as prior art.

[0015] Many technical processes for migrating storage objects (such as volumes and storage virtual machines) are disruptive to the client. These migration processes may be limited to performing asynchronous transfers of data from a source storage object to a destination storage object. These asynchronous transfers copy incremental changes to the data of the source storage object to the destination storage object. After the asynchronous transfer is completed, the I / O from the client to the source storage object is isolated / stopped (blocked). For applications and computers that rely on access to the data of the source storage object because the I / O is blocked (such as failed or queued for later execution), this will result in significant client wait times. Therefore, during the cutover period when the client is cutover from being able to access the source storage object to being able to access the destination storage object, the client may experience higher wait times due to the isolation / stopping of I / O. This may cause application and computer timeouts, crashes, or other operational issues and downtime.

[0016] Therefore, these migration processes are improved by performing non-disruptive migrations that reduce the disruptiveness and client latency associated with migrating storage objects. This improvement is achieved by additionally utilizing a synchronous replication process during the migration process. The advantage of using synchronous replication is that the latency experienced by the client can be greatly reduced. In addition, synchronous replication is also used to achieve successful non-disruptive migration of storage virtual machines as a collection of volumes.

[0017] In one embodiment, an asynchronous replication process is performed to asynchronously replicate incremental changes to data of a storage object to a replicated storage object. For example, changes to data within a volume of a storage virtual machine stored across multiple nodes of a first cluster are asynchronously replicated to a replicated volume of a replicated storage virtual machine at a second cluster. This is performed as part of a non-disruptive migration process to migrate a storage virtual machine from a first cluster to a second cluster to improve performance or more efficiently utilize storage capacity (e.g., the second cluster may have more available storage resources and / or processing resources).

[0018] An asynchronous incremental transfer is performed until a cutover criterion is met. The cutover criterion may be defined as a set amount of time or an amount of remaining data to be copied. Thus, in response to the cutover criterion being met, a synchronous replication process is performed. The synchronous replication process is performed to synchronously replicate operations targeting the storage object. The operations are performed on the storage object and replicated to create replication operations, which are transmitted to the second cluster for execution on the replicated storage object. In response to receiving a confirmation message from the second cluster that the replication operation has been received, a confirmation of successful completion of the operation is returned to the client computing device that generated the operation.

[0019] The transmission of the confirmation message is based on the second cluster receiving the replication operation for subsequent execution on the replicated storage object, rather than submitting the replication operation, so the waiting time for the client computing device is very short. Otherwise, the client computing device will experience a longer waiting time because the successful confirmation message will not be sent to the client computing device until after the replication operation is submitted. This also allows the second cluster to queue the replication operation so that the replication operation can be submitted to the storage in a manner that ensures the slave write order consistency of the order in which the corresponding operation is performed by the first cluster. For example, a first write operation writes data A to the storage object, and a second write operation overwrites data A with data B. If the second cluster performs the replication of the second write operation before the replication of the first write operation, data inconsistency will occur because the second cluster will now store data A, while the first cluster will store data B.

[0020] Once all child objects of the storage object (e.g., each volume storing the virtual machine) are in a stable state of synchronous replication with the replicated storage object (e.g., operations and replication operations are being submitted to the storage), the cutover phase is performed. The cutover phase is performed to switch clients from accessing the storage object to accessing the replicated storage object. The cutover window during the cutover phase, where client I / O is stopped, is shorter than conventional migration techniques because the cutover can be performed quickly because the storage object and the replicated storage object are in a stable synchronized state, so less time is spent synchronizing any remaining data. Even if both replicas are already synchronized (the storage object and the replicated storage object are synchronized), there is a latency improvement / benefit because only a few pending I / Os on the replicated storage object (the secondary replica) will be exhausted during the cutover phase. These I / Os are exhausted during the cutover phase, so this is the only time period when I / O is stopped because synchronous replication is used as the underlying engine for the migration.

[0021] During the cutover phase, client I / O is stopped and the last operations are performed to complete any pending running operations and replication operations (e.g., running operations include operations that have not yet been committed to storage objects and replication storage objects). Any other file system metadata (such as Network File System (NFS) lock data, replay caches for non-idempotent operations, etc.) will be transmitted to the second cluster. Once completed, the client is redirected to the replication storage object. In contrast, existing migration technologies will have to perform additional data replication to put the storage object and the replication storage object into a consistent state. This will increase client latency and adversely affect client throughput. Accordingly, synchronous replication is performed before the cutover in order to reduce latency and improve client throughput because the time that client I / O is stopped is reduced because there is little additional data to copy (e.g., only running operations need to be exhausted and file system metadata needs to be copied over).

[0022] This non-disruptive migration technology also provides other improvements over existing migration technologies. For example, existing migration technologies may not be able to migrate multiple volumes between clusters in a predictable manner. In contrast, this non-disruptive migration technology can migrate storage virtual volumes in multiple volumes that are stored across multiple nodes in a predictable manner. Even though each volume is independent of each other and may have different data change rates, the migration is still performed in a predictable manner because synchronous replication puts the storage volume and the replicated storage volume into a stable state of synchronous replication before the cutover. This also allows for more relaxed cutover criteria to be specified. Otherwise, existing migration technologies that only use asynchronous replication must meet strict cutover criteria, which may result in the failure of a cutover attempt that cannot be completed within the time limit set by such strict cutover criteria.

[0023] To provide seamless migration, Figure 1An embodiment of a cluster network environment 100 or a network storage environment is shown. However, it is understood that the techniques described herein, etc. can be implemented in a cluster network environment 100, a non-cluster network environment, and / or various other computing environments (such as a desktop computing environment). That is, the present disclosure, including the scope of the appended claims, is not intended to be limited to the examples provided herein. It is understood that if the same or similar components, elements, features, items, modules, etc. are shown in subsequent figures but have been previously discussed with respect to previous figures, their similar (e.g., redundant) discussions can be omitted when describing subsequent figures (e.g., for the purpose of simplicity and ease of understanding).

[0024] Figure 1 1 is a block diagram illustrating a cluster network environment 100 in which at least some embodiments of the techniques and / or systems described herein may be implemented. The cluster network environment 100 includes data storage systems 102 and 104 coupled via a cluster fabric 106, such as a computing network embodied as a private Infiniband, Fibre Channel (FC), or Ethernet, to facilitate communications between the data storage systems 102 and 104 (and one or more modules, components, etc. therein, such as nodes 116 and 118). It should be understood that although in Figure 1 102 and 104 and two nodes 116 and 118 are shown, but any suitable number of such components is contemplated. In one example, nodes 116, 118 include a storage controller (e.g., node 116 may include a primary or local storage controller, and node 118 may include a secondary or remote storage controller) that provides access to data stored in data storage devices 128, 130 to client devices such as host devices 108, 110. Similarly, other modules, elements, features, items, etc. referenced herein and / or shown in the accompanying drawings are also the same unless otherwise specifically provided herein. That is, the specific number of components, modules, elements, features, items, etc. disclosed herein should not be interpreted in a limiting manner.

[0025] It will be further appreciated that the cluster network is not limited to any particular geographic region and may be clustered locally and / or remotely. Thus, in one embodiment, the cluster network may be distributed across multiple storage systems and / or nodes located in multiple geographic locations. In one embodiment, the cluster network may include data storage systems (e.g., 102, 104) that reside in the same geographic location (e.g., in a single on-site rack of data storage devices).

[0026] In the example shown, one or more host devices 108, 110 (which may include, for example, client devices, personal computers (PCs), computing devices for storage (e.g., storage servers), and other computers or peripheral devices (e.g., printers)) are coupled to respective data storage systems 102, 104 via storage network connections 112, 114. The network connection may include a local area network (LAN) or a wide area network (WAN) that utilizes, for example, a network attached storage (NAS) protocol (such as the Common Internet File System (CIFS) protocol or the Network File System (NFS) protocol for exchanging data packets), a storage area network (SAN) protocol (such as the Small Computer System Interface (SCSI) or the Fibre Channel Protocol (FCP)), an object protocol (such as S3), etc. Illustratively, the host devices 108, 110 may be general purpose computers running applications and may interact with the data storage systems 102, 104 using a client / server model to exchange information. That is, the host device can request data from the data storage system (e.g., data on a storage device managed by a network storage control that is configured to process I / O commands issued by the host device for the storage device), and the data storage system can return the results of the request to the host device via one or more storage network connections 112, 114.

[0027] The nodes 116, 118 on the clustered data storage systems 102, 104 may include network or host nodes that are interconnected as a cluster to provide data storage and management services, such as to enterprises with remote locations, cloud storage (e.g., storage endpoints may be stored in a data cloud), etc. For example, such a node in the clustered network environment 100 may be a device attached to the network as a connection point, a redistribution point, or a communication endpoint. The node may be capable of sending, receiving, and / or forwarding information over a network communication channel, and may include any device that meets any or all of these conditions. An example of a node may be a data storage and management server connected to a network, wherein the server may include a general-purpose computer or computing device that is specifically configured to be used as a server in a data storage and management system.

[0028] In one example, a first cluster of nodes, such as nodes 116, 118, etc., may be located at a first storage site (e.g., a first set of storage controllers configured to provide access to a first storage set including a first logical grouping of one or more storage devices). A second node cluster, not shown, may be located at a second storage site (e.g., a second set of storage controllers configured to provide access to a second storage set including a second logical grouping of one or more storage devices). The first node cluster and the second node cluster may be configured according to a disaster recovery configuration, wherein if a disaster occurs at a disaster storage site including the disaster node cluster, the surviving node cluster provides switched access to the storage devices of the disaster node cluster (e.g., if a disaster occurs at the second storage site, the first node cluster provides client devices with switched data access to the storage devices of the second storage set).

[0029] As shown in the cluster network environment 100, the nodes 116, 118 may include various functional components that collaborate to provide a distributed storage architecture for the cluster. For example, the nodes may include network modules 120, 122 and disk modules 124, 126. The network modules 120, 122 may be configured to allow the nodes 116, 118 (e.g., network storage controllers) to connect to host devices 108, 110 via storage network connections 112, 114, for example, to allow the host devices 108, 110 to access data stored in the distributed storage system. In addition, the network modules 120, 122 may provide connectivity to one or more other components via the cluster structure 106. For example, in Figure 1 , the network module 120 of the node 116 may access the second data storage device by sending a request through the disk module 126 of the node 118 .

[0030] The disk modules 124, 126 may be configured to connect one or more data storage devices 128, 130 (such as disks or disk arrays, flash memory, or some other form of data storage) to the nodes 116, 118. The nodes 116, 118 may be interconnected through the cluster fabric 106, for example, to allow a respective node in the cluster to access data on a data storage device 128, 130 connected to a different node in the cluster. Typically, the disk modules 124, 126 communicate with the data storage devices 128, 130 according to a SAN protocol such as SCSI or FCP, for example. Thus, as seen from an operating system on the nodes 116, 118, the data storage devices 128, 130 appear to be locally attached to the operating system. In this manner, different nodes 116, 118, etc. may access blocks of data through the operating system, rather than explicitly requesting abstract files.

[0031] It should be understood that although the cluster network environment 100 shows an equal number of network and disk modules, other embodiments may include different numbers of these modules. For example, there may be multiple interconnected network and disk modules in a cluster without a one-to-one correspondence between the network and the disk modules. That is, different nodes may have different numbers of network and disk modules, and the same node may have a different number of network modules than disk modules.

[0032] In addition, the host devices 108, 110 may be networked with the nodes 116, 118 in the cluster through the storage networking connections 112, 114. As an example, the respective host devices 108, 110 networked to the cluster may request services (e.g., exchange information in the form of data packets) of the nodes 116, 118 in the cluster, and the nodes 116, 118 may return the results of the requested services to the host devices 108, 110. In one embodiment, the host devices 108, 110 may exchange information with the network modules 120, 122 residing in the nodes 116, 118 (e.g., network hosts) in the data storage systems 102, 104.

[0033] In one embodiment, data storage device 128,130 comprises volume 132, and volume 132 is the realization that information is stored on disk drive or disk array or other storage (for example, flash memory) as the file system for data.In one example, disk array can comprise all conventional hard disk drives, all flash drives, or the combination of conventional hard disk drives and flash drives.For example, volume can span a part of disk, disk set or partial disk, and generally defines the overall logical arrangement of file storage on the disk space in storage system.In one embodiment, volume can comprise the storage data of one or more files in the hierarchical directory structure as residing in the volume.

[0034] Volumes are typically configured in a format that can be associated with a particular storage system, and the corresponding volume format typically includes features that provide functionality for the volume, such as providing the ability for the volumes to form clusters. For example, where a first storage system may use a first format for its volumes, a second storage system may use a second format for its volumes.

[0035] In the cluster network environment 100, the host devices 108, 110 can utilize the data storage systems 102, 104 to store and retrieve data from the volume 132. In this embodiment, for example, the host device 108 can send a data packet to the network module 120 in the node 116 within the storage device 102. The node 116 can use the disk module 124 to forward the data to the data storage device 128, wherein the data storage device 128 includes the volume 132A. In this way, in this example, the host device can use the data storage system 102 connected through the storage network connection 112 to access the volume 132A to store and / or retrieve data. In addition, in this embodiment, the host device 110 can exchange data with the network module 122 in the node 118 within the data storage system 104 (for example, it can be far away from the data storage system 102). The node 118 can use the disk module 126 to forward the data to the data storage device 130, thereby accessing the volume 132B associated with the data storage device 130.

[0036] It will be appreciated that replay of metadata and data operations may be implemented within the cluster network environment 100. In one example, operations may be performed at the node 116 and replayed at the node 118. It will be appreciated that replay of metadata and data operations may be implemented for and / or between any type of computing environment, and may be transportable between physical devices (e.g., nodes 116, nodes 118, desktop computers, tablet computers, notebook computers, wearable devices, mobile devices, storage devices, servers, etc.) and / or cloud computing environments (e.g., remote from the cluster network environment 100).

[0037] Figure 2 is a data storage system 200 (e.g., Figure 1 102, 104) in the illustrative example, which provides more details of an embodiment of a component that can implement one or more techniques and / or systems described herein. Data storage system 200 includes node 202 (e.g., Figure 1 116, 118) and a data storage device 234 (e.g., Figure 1 Node 202 may be, for example, a general purpose computer or some other computing device specifically configured to function as a storage server. Host device 205 (e.g., Figure 1 108, 110) can be connected to the node 202 via the network 216, for example, to provide access to files and / or other data stored on the data storage device 234. For example, the node 202 includes a storage controller that provides access to data stored in the data storage device 234 to client devices such as the host device 205.

[0038] The data storage device 234 may include a mass storage device, such as the disks 224, 226, 228 of the disk arrays 218, 220, 222. It should be understood that the techniques and systems described herein are not limited to the example embodiments. For example, the disks 224, 226, 228 may include any type of mass storage device, including but not limited to disk drives, flash memory, and any other similar media suitable for storing information, including, for example, data (D) and / or parity (P) information.

[0039] The node 202 includes one or more processors 204, a memory 206, a network adapter 210, a cluster access adapter 212, and a storage adapter 214 interconnected by a system bus 242. The data storage system 200 also includes an operating system 208 installed in the memory 206 of the node 202, and the operating system 208 can, for example, implement a redundant array of independent (or inexpensive) disks (RAID) optimization technology to optimize the reconstruction process of data of a failed disk in the array.

[0040] The operating system 208 may also manage communications for the data storage system and may be located in a cluster network such as attached to a cluster fabric 215 (eg, Figure 1 106 in the cluster network system). Therefore, nodes 202 such as network storage controllers can respond to host device requests to manage data on data storage devices 234 (e.g., or other cluster devices) according to these host device requests. For example, the operating system 208 can typically establish one or more file systems on the data storage system 200, where the file system can include software code and data structures that implement a persistent hierarchical name space for files and directories. As an example, when a new data storage device (not shown) is added to the cluster network system, the operating system 208 is notified where new files associated with the new data storage device will be stored in the existing directory tree. This is generally referred to as "mounting" a file system.

[0041] In the example data storage system 200, the memory 206 may include storage locations addressable by the processor 204 and adapters 210, 212, 214 for storing related software application code and data structures. The processor 204 and the adapters 210, 212, 214 may, for example, include processing elements and / or logic circuitry configured to execute software code and manipulate data structures. An operating system 208 (portions of which typically reside in the memory 206 and are executed by the processing elements) functionally organizes the storage system by invoking storage operations to support file services implemented by the storage system, etc. It will be clear to those skilled in the art that other processing and storage mechanisms (including various computer-readable media) may be used to store and / or execute application instructions related to the techniques described herein. For example, the operating system may also utilize one or more control files (not shown) to help provide a virtual machine.

[0042] The network adapter 210 includes the mechanical, electrical, and signaling circuitry required to connect the data storage system 200 to the host device 205 via a network 216, which may include a point-to-point connection or a shared medium, such as a local area network. Figure 1 108, 110) can be a general-purpose computer configured to execute an application. As described above, the host device 205 can interact with the data storage system 200 according to a client / host model of information transfer.

[0043] The storage adapter 214 cooperates with the operating system 208 executed on the node 202 to access information requested by the host device 205 (e.g., access data on a storage device managed by a network storage controller). The information can be stored on any type of attached writable media array, such as a disk drive, flash memory, and / or any other similar medium suitable for storing information. In the example data storage system 200, the information can be stored in data blocks on the disks 224, 226, 228. The storage adapter 214 may include an input / output (I / O) interface circuit system that is coupled to the disks via an I / O interconnect arrangement such as a storage area network (SAN) protocol (e.g., small computer system interface (SCSI), iSCSI, hyperSCSI, Fibre Channel Protocol (FCP)). The information is retrieved by the storage adapter 214 and processed, if necessary, by one or more processors 204 (or the storage adapter 214 itself), and then forwarded via the system bus 242 to the network adapter 210 (and / or cluster access adapter 212, if sending to another node in the cluster), where the information is formatted into data packets and returned to the host device 205 via the network 216 (and / or returned to another node attached to the cluster via the cluster fabric 215).

[0044] In one embodiment, information storage on disk arrays 218, 220, 222 can be implemented as one or more storage volumes 230, 232, which are composed of clusters of disks 224, 226, 228 that define an overall logical arrangement of disk space. The disks 224, 226, 228 that comprise one or more volumes are typically organized into one or more RAID groups. As an example, volume 230 comprises a collection of disk arrays 218 and 220, which comprise clusters of disks 224 and 226.

[0045] In one embodiment, to facilitate access to disks 224, 226, 228, operating system 208 may implement a file system (e.g., write file system anywhere) that logically organizes information into a hierarchical structure of directories and files on the disks. In this embodiment, respective files may be implemented as a set of disk blocks configured to store information, and directories may be implemented as specially formatted files in which information about other files and directories is stored.

[0046] Regardless of the underlying physical configuration within the data storage system 200, data may be stored as files in physical and / or virtual volumes, which may be associated with corresponding volume identifiers, such as file system identifiers (FSIDs), which may be 32 bits in length in one example.

[0047] A physical volume corresponds to at least a portion of a physical storage device whose address, addressable space, location, etc. does not change, such as at least some of one or more data storage devices 234 (e.g., a redundant array of independent (or inexpensive) disks (RAID system)). Typically, the location of a physical volume does not change because the address (ranges) used to access the physical volume typically remain unchanged.

[0048] Instead, a virtual volume is stored on a collection of different portions of different physical storage devices. A virtual volume may be a collection of different available portions of different physical storage device locations, such as some available space from each of disks 224, 226, and / or 228. It should be appreciated that because a virtual volume is not "bound" to any one particular storage device, it can be said that the virtual volume includes an abstraction layer or virtualization layer that makes it resizable and / or flexible in certain aspects.

[0049] In addition, the virtual volume may include one or more logical unit numbers (LUNs) 238, directories 236, Qtrees 235, and files 240. These features (specifically LUNs) allow, among other things, different storage locations in which data is stored to be identified and grouped as data storage units. Thus, LUNs 238 may be characterized as constituting a virtual disk or drive on which data within the virtual volume is stored. For example, LUNs are often referred to as virtual drives so that they can emulate hard disk drives in general-purpose computers, while they actually include blocks of data stored in various portions of the volume.

[0050] In one embodiment, one or more data storage devices 234 may have one or more physical ports, wherein each physical port may be assigned a target address (e.g., a SCSI target address). To represent a corresponding volume stored on the data storage device, the target address on the data storage device may be used to identify one or more LUNs 238. Thus, for example, when a node 202 is connected to a volume 230, 232 via a storage adapter 214, a connection is created between the node 202 and the one or more LUNs 238 underlying the volume.

[0051] In one embodiment, the corresponding target address can identify multiple LUNs, so that the target address can represent multiple volumes. For example, an I / O interface that can be implemented as circuitry and / or software in storage adapter 214 or as executable code resident in memory 206 and executed by processor 204 can connect to volume 230 by using one or more addresses identifying one or more LUNs 238.

[0052] It will be appreciated that replay of metadata and data operations may be implemented for the data storage system 200. In one example, the node 202 may perform operations on the NVRAM and replay the operations to flush the NVRAM into storage. It will be appreciated that replay of metadata and data operations may be implemented for and / or between any type of computing environment and may be transferable between physical devices (e.g., the node 202, the host device 205, a desktop computer, a tablet computer, a notebook computer, a wearable device, a mobile device, a storage device, a server, etc.) and / or a cloud computing environment (e.g., remote from the node 202 and / or the host device 205).

[0053] An embodiment of a cutover engine based on synchronous replication is composed of Figure 3 An exemplary method 300 is shown and combined with Figure 4A The system 400 of FIG. 4D is further described. The first computing environment 402 includes storage objects 404, such as files, directories, volumes, storage virtual machines, etc. Figure 4AAs shown. In one embodiment, storage object 404 may include storage virtual machines of multiple volumes stored across multiple nodes of the first cluster. Second computing environment 406 may maintain replicated storage object 408 as a copy of storage object 404. Replicated storage object 408 may include replicated virtual machines of multiple replicated volumes stored across multiple nodes of the second cluster. The replication process may be used to replicate data within storage object 404 and replicate operations such as data operations and metadata operations (e.g., write / modify operations) directed to storage object 404 to replicated storage object 408.

[0054] It may be determined that storage object 404 should be migrated to second computing environment 406 as replicated storage object 408. In one embodiment, as part of the migration, replicated storage object 408 is created within second computing environment 406, and a replication process is performed to replicate data into replicated storage object 408. In one embodiment, the determination may be made based on receiving a migration command. In one embodiment, performance statistics of first computing environment 402 are evaluated against performance criteria to determine that migration should be performed based on the performance statistics not satisfying the performance criteria. In one embodiment, storage capacity statistics of first computing environment 402 are evaluated against storage capacity criteria to determine that migration should be performed based on the storage capacity statistics not satisfying the storage capacity criteria. In this manner, a replication process is performed to migrate storage object 404 to second computing environment 406 as replicated storage object 408.

[0055] At 302, an asynchronous replication process 410 is executed to perform an asynchronous incremental transfer of data of the storage object 404 from the first computing environment 402 to the replicated storage object 408 until the cutover criteria are met, such as Figure 4A In one embodiment, the cutover criterion may be defined as a time span for performing asynchronous replication (e.g., the cutover criterion corresponds to a 3 minute time span during which asynchronous replication will be performed). In one embodiment, the cutover criterion may be defined as an amount of remaining data to be replicated (e.g., the cutover criterion corresponds to a percentage of remaining data to be replicated (such as 5%) or a size of remaining data to be replicated (such as 50 megabytes)).

[0056] At 304, a synchronous replication process 412 is performed based on the cutover criteria being met to synchronously replicate operations (e.g., data operations, metadata operations, write operations, etc.) targeting the storage object 404 to the replicated storage object 408, such as Figure 4BIn the case of synchronous replication, a client submitting an operation to first computing environment 402 for execution on storage object 404 is not acknowledged as having had an operation successfully until both the operation and the replication of the operation are acknowledged (e.g., the operation is submitted to storage object 404 and second computing environment 406 acknowledges receipt of the replication operation for submission on replicated storage object 408).

[0057] In an embodiment of the replication process, an operation (e.g., a write operation) is performed on a storage object 404, and then the operation is transmitted as a replication operation to a second computing environment 406 for execution on a replication storage object 408. The operation is executed according to a defined order. Therefore, a sequence number is assigned to the replication operation based on the execution order. The sequence number is used by the second computing environment 406 to enforce the execution of the replication operation on the replication storage object 408 according to the defined order. Specifically, the second computing environment 406 can transmit a message confirming that the replication operation has been received, so that the first computing environment 402 can confirm to the client that the operation has been successful when submitting to the storage object 404. The second computing environment 406 can queue the replication operation in a queue. The second computing environment 406 can sort / sequence the replication operation based on the assigned sequence number, so that the sorted replication operation corresponds to the execution order of the first computing environment 402. In this way, the second computing environment 406 can perform the replication operation on the replication storage object 408 according to a similar execution order.

[0058] At 306, a cutover 414 is performed to direct operations (e.g., write and read requests) from targeting storage object 404 to targeting replicated storage object 408 when the cutover 414 is complete. Figure 4C 4D. Cutover 414 is performed based on the synchronous replication process reaching a stable state of synchronous replication for sub-objects (e.g., files, directories, data blocks or other sub-objects of one or more volumes of a storage virtual machine) of storage object 404. The stable state is a state in which operations are submitted to both storage object 404 and replicated storage object 408.

[0059] In an embodiment of cutover 414, the application that created the operation is stopped to suspend the application's generation of operations targeting storage object 404. A drain operation is performed to complete pending operations that have not yet been submitted for storage (e.g., in-flight operations, such as replication operations that have not yet been submitted to replicated storage object 408 by the second computing environment). Protocol specific information (such as network file system lock data and replay caches for non-idempotent operations) is copied to replicated storage object 408. Because storage object 404 and replicated storage object 408 are synchronized with a synchronous replication process, the number of operations that need to be drained (completed) is relatively small, and therefore the period of time that I / O from the application is stopped is short.

[0060] Once the cutover 414 is complete, the applications and / or other remote devices are now switched to access the replicated storage object 408 instead of the storage object 404. In this manner, the client I / O 401 is redirected to the replicated storage object 408 at the second computing environment 406. If the storage object 404 fails to be migrated, a rollback of the replicated storage object 408 to the state when the last asynchronous incremental transfer was performed is performed using the snapshot created by the last asynchronous incremental transfer. That is, the snapshot is used to modify the replicated storage object 408 to include the data that the replicated storage object 408 included after the last asynchronous incremental transfer was performed on the replicated storage object 408.

[0061] In one embodiment, a timestamp matching process is performed to match the timestamps of the file system modification operations with the metadata of the first computing environment 402 and the second computing environment 406. In an embodiment of the timestamp matching process, synchronous replication processes incoming operations in a sequential manner (e.g., the operation is first processed on the primary storage object and then replicated to the secondary storage object).

[0062] As part of processing an operation, the primary file system will modify various timestamps associated with a storage object (e.g., inode), such as mtime (modification time), ctime (state change time), and crtime (creation time). In response to the operation, synchronous replication will obtain the modified timestamp (mtime). Synchronous replication will copy the modified timestamp to the secondary storage object. The above situation can also be well applied when the operations are processed in a serial manner, such as if each operation is first written to the primary storage object and then to the secondary storage object. However, this cannot be used as an operating mode due to performance considerations, so data operations are processed in parallel (e.g., although multiple write operations can be performed in parallel in a sequential manner). Since the order of operations is not maintained at the second computing environment 406, the order of operations performed on the primary storage object and the secondary storage object can be different. This may result in a timestamp mismatch between the primary storage object and the secondary storage. One way to solve this inconsistency problem is to teach the file system not to modify the timestamp when the current timestamp on the inode is already higher than the timestamp of the current operation.

[0063] In one embodiment, a method includes performing a timestamp matching process to match a timestamp of a file system modification operation with metadata of a first computing environment 402 and a second computing environment 406. In one embodiment, the method includes evaluating performance statistics of the first computing environment 402 against a performance criterion to determine that a storage object 404 is to be migrated to the second computing environment 406 as a replicated storage object 408 based on the performance statistics being less than the performance criterion. In one embodiment, the method includes evaluating storage capacity statistics of the first computing environment 402 against a capacity criterion to determine that the storage object 404 is to be migrated to the second computing environment 406 as a replicated storage object 408 based on the storage capacity statistics being less than the capacity criterion.

[0064] In one embodiment, the method includes performing the operation on the storage object 404 before transmitting the operation to the second computing environment 406 for execution on the replicated storage object 408, and includes performing the operation according to a defined order, and assigning a sequence number to the replication operation for enforcement by the second computing environment 406 to perform the replication operation according to the defined order based on the sequence number. In one embodiment, the method includes performing a rollback of the replicated storage object 408 using a snapshot created by a last asynchronous incremental transfer based on detecting a failure to migrate the storage object to the second computing environment 406 as the replicated storage object 408.

[0065] Another embodiment involves a computer-readable medium including processor-executable instructions configured to implement one or more of the techniques presented herein. Figure 5 , wherein an example embodiment of a computer-readable medium or computer-readable device designed in these ways is shown, wherein the implementation includes a computer-readable medium 508 having computer-readable data 506 recorded thereon, such as a recordable compact disk (CD-R), a recordable digital versatile disk (DVD-R), a flash drive, a hard drive platter, etc. The computer-readable data 506 (such as binary data including at least one of 0 or 1) further includes processor-executable computer instructions 504 configured to operate according to one or more principles set forth herein. In some embodiments, for example, the processor-executable computer instructions 504 are configured to perform a method 502, such as Figure 3 In some embodiments, for example, the processor-executable computer instructions 504 are configured to implement a system such as Figure 4A It is contemplated that many such computer-readable media will operate in accordance with the techniques presented herein.

[0066] Figure 66 is a diagram illustrating an example operating environment 600 in which embodiments of the techniques described herein may be implemented. In one example, the techniques described herein may be implemented within a client device 628, such as a laptop computer, a tablet computer, a personal computer, a mobile device, a wearable device, and the like. In another example, the techniques described herein may be implemented within a storage controller 630 (such as a node) configured to manage storage and access to data on behalf of the client device 628 and / or other client devices. In another example, the techniques described herein may be implemented within a distributed computing platform 602 (such as a cloud computing environment (e.g., a cloud storage environment, a multi-tenant platform, etc.) configured to manage storage and access to data on behalf of the client device 628 and / or other client devices.

[0067] In yet another example, at least some of the techniques described herein are implemented on one or more of the client device 628, the storage controller 630, and the distributed computing platform 602. For example, the client device 628 may transmit operations (such as data operations to read data and write data, and metadata operations (e.g., create file operations, rename directory operations, resize operations, set attribute operations, etc.)) to the storage controller 630 over the network 626 to be implemented by the storage controller 630 at the time of storage. The storage controller 630 may store data associated with operations within volumes or other data objects / structures hosted in locally attached storage, remote storage hosted by other computing devices accessible over the network 626, storage provided by the distributed computing platform 602, and the like. The storage controller 630 may replicate the data and / or operations to other computing devices in order to maintain one or more copies, such as a destination storage volume maintained as a copy of a source storage volume. Such copies may be used for disaster recovery and failover.

[0068] By transferring the data to the distributed computing platform 602, the storage controller 630 may store the data or a portion thereof in storage hosted by the distributed computing platform 602. In one example, the storage controller 630 may store frequently accessed data locally in locally attached storage. Data that is less frequently accessed may be transferred to the distributed computing platform 602 to be stored in the data storage layer 608. The data storage layer 608 may store the data in the service data repository 620, and may store client-specific data in client data repositories assigned to such data, such as a client (1) data repository 622 for storing data of client (1) and a client (N) data repository 624 for storing data of client (N). The data storage may be a physical storage device, or may be defined as a logical storage that may be defined across one or more physical storage devices, such as a virtual volume, LUN, or other logical organization of data. In another example, the storage controller 630 transfers and stores all client data to the distributed computing platform 602. In yet another example, the client device 628 transfers and stores the data directly to the distributed computing platform 602 without using the storage controller 630.

[0069] Management of storage and access to data may be performed by one or more storage virtual machines (SVMs) or other storage applications that provide software as a service (SaaS), such as storage software services. In one example, the SVMs may be hosted within the client device 628, within the storage controller 630, or within the distributed computing platform 602, such as by the application server layer 606. In another example, one or more SVMs may be hosted on one or more of the client device 628, the storage controller 630, and the distributed computing platform 602.

[0070] In one example of the distributed computing platform 602, one or more SVMs may be hosted by the application server layer 606. For example, the server (1) 616 is configured to host an SVM for executing an application (such as a storage application) for managing data storage of the client (1) within the client (1) data repository 622. Thus, the SVM executing on the server (1) 616 may receive data and / or operations from the client device 628 and / or the storage controller 630 via the network 626. The SVM executes the storage application to process the operation and / or store the data within the client (1) data repository 622. The SVM may transmit a response, such as a success message or an error message, back to the client device 628 and / or the storage controller 630 via the network 626. In this manner, the application server layer 606 may use the server (1) 616, the server (N) 618, etc. to host SVMs, services, and / or other storage applications.

[0071] The user interface layer 604 of the distributed computing platform 602 can provide the client device 628 and / or the storage controller 630 with access to user interfaces associated with storing and accessing data and / or other services provided by the distributed computing platform 602. In one example, a service user interface 610 can be accessible from the distributed computing platform 602 to access services subscribed by the client and / or the storage controller, such as data replication services, application hosting services, data security services, human resources services, warehouse tracking services, accounting services, etc. For example, client user interfaces can be provided to corresponding clients, such as client (1) user interface 612, client (N) user interface 614, etc. Client (1) can access various services and resources subscribed by client (1) through client (1) user interface 612, such as access to web services, development environments, human resources applications, warehouse tracking applications, and / or other services and resources provided by the application server layer 606, which can use data stored in the data storage layer 608.

[0072] The client device 628 and / or the storage controller 630 may subscribe to certain types and amounts of services and resources provided by the distributed computing platform 602. For example, the client device 628 may establish a subscription to access three virtual machines, a certain amount of storage, a certain type / amount of data redundancy, a certain type / amount of data security, certain service level agreements (SLAs) and service level objectives (SLOs), latency guarantees, bandwidth guarantees, access for executing or hosting certain applications, etc. Similarly, the storage controller 630 may establish a subscription to access certain services and resources of the distributed computing platform 602.

[0073] As shown, various clients incorporated with and / or into various computing devices, such as client device 628 and storage controller 630, may communicate with distributed computing platform 602 via one or more networks, such as network 625. For example, a client may be incorporated with and / or into a client application (e.g., software) that is implemented at least in part by one or more computing devices.

[0074] Examples of suitable computing devices include personal computers, server computers, desktop computers, nodes, storage servers, storage controllers, laptop computers, notebook computers, tablet computers or personal digital assistants (PDAs), smart phones, cell phones, and consumer electronic devices incorporating one or more computing device components, such as one or more electronic processors, microprocessors, central processing units (CPUs), or controllers. Examples of suitable networks include networks utilizing wired and / or wireless communication technologies, and networks operating according to any suitable networking and / or communication protocols (e.g., the Internet). In use cases involving the delivery of customer support services, the labeled computing device represents the endpoint of the customer support delivery process, i.e., the consumer's device.

[0075] A distributed computing platform 602 (such as a multi-tenant business data processing platform or a cloud computing environment) may include multiple processing layers, including a user interface layer 604, an application server layer 606, and a data storage layer 608. The user interface layer 604 may maintain multiple user interfaces, including graphical user interfaces and / or web-based interfaces. The user interface may include a service user interface 610 for a service to provide access to applications and data of clients (e.g., "tenants") of the service, and the user interface may also include one or more user interfaces that have been specialized / customized according to the specific requirements of the user, which may be accessed via one or more APIs.

[0076] The service user interface 610 may include components that enable tenants to manage their participation in the functions and capabilities provided by the distributed computing platform 602, such as accessing data, causing the execution of specific data processing operations, etc. Each processing layer may be implemented with a set of computers, a virtualized computing environment such as a storage virtual machine or storage virtual server, and / or computer components including computer servers and processors, and may perform various functions, methods, processes, or operations determined by the execution of a software application or instruction set.

[0077] The data storage layer 608 may include one or more data repositories, which may include a service data repository 620 and one or more client data repositories. Each customer data repository may contain tenant-specific data used as part of providing a range of tenant-specific business and storage services or functions, including but not limited to ERP, CRM, e-commerce, human resource management, payroll, storage services, etc. The data repository may be implemented using any suitable data storage technology, including a relational database management system (RDBMS) based on structured query language (SQL), a file system hosted by an operating system, object storage, etc.

[0078] According to one embodiment of the present invention, the distributed computing platform 602 can be a multi-tenant and service platform operated by an entity to provide a set of business-related applications, data storage, and functions to multiple tenants. These applications and functions may include applications and functions used by an enterprise to manage various aspects of its operations. For example, the applications and functions may include providing network-based access to business information systems, thereby allowing users with a browser and an Internet or intranet connection to view, enter, process, or modify certain types of business information or any other type of information.

[0079] In one embodiment, the described methods and / or their equivalents may be implemented with computer executable instructions. Thus, in one embodiment, a non-transitory computer readable / storage medium is configured with stored computer executable instructions of an algorithm / executable application, which, when executed by (multiple) machines, causes (multiple) machines (and / or related components) to perform the method. Example machines include, but are not limited to, processors, computers, servers operating in a cloud computing system, servers configured in a software as a service (SaaS) architecture, smart phones, etc. In one embodiment, a computing device is implemented with one or more executable algorithms configured to perform any disclosed method.

[0080] It should be understood that the processes, architectures, and / or procedures described herein can be implemented in hardware, firmware, and / or software. It should also be understood that the provisions set forth herein can be applicable to any type of special-purpose computer (e.g., a file host, storage server, and / or storage service device) and / or general-purpose computer embodied as or including a storage system, including a stand-alone computer or portion thereof. In addition, the teachings herein can be configured as various storage system architectures, including but not limited to network-attached storage environments, and / or storage area networks and disk components directly attached to a client or host. Therefore, in addition to any subsystem configured to perform storage functions and associated with other devices or systems, the storage system should be broadly included in such an arrangement.

[0081] In some embodiments, the method described and / or shown in the present disclosure can be implemented in whole or in part on a computer-readable medium. A computer-readable medium may include a processor executable instruction configured to implement one or more methods proposed herein, and may include any mechanism for storing the data, which can be read by a computer system afterwards. Examples of computer-readable media include (hard) drives (e.g., accessible via network attached storage (NAS)), storage area networks (SANs), volatile and non-volatile memories, such as read-only memories (ROMs), random access memories (RAMs), electrically erasable programmable read-only memories (EEPROMs) and / or flash memories, compact disk read-only memories (CD-ROMs), CD-Rs, rewritable compact disks (CD-RWs), DVDs, cassettes, tapes, disk storage, optical or non-optical data storage devices, and / or any other medium that can be used to store data.

[0082] Although the subject matter has been described in language specific to structural features or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing at least some of the claims.

[0083] Various operations of the embodiments are provided herein. The order of describing some or all operations should not be interpreted as implying that these operations are necessarily related to the order. In view of the benefit of this specification, alternative ordering will be understood. In addition, it is understood that not all operations must exist in each embodiment provided herein. Moreover, it should be understood that not all operations are required in some embodiments.

[0084] In addition, the claimed subject matter may be implemented as a method, apparatus, or article of manufacture using standard application or engineering techniques to produce software, firmware, hardware, or any combination thereof to control a computer to implement the disclosed subject matter. The term "article of manufacture" as used herein is intended to encompass a computer application accessible from any computer-readable device, carrier, or medium. Of course, many modifications may be made to this configuration without departing from the scope or spirit of the claimed subject matter.

[0085] As used in this application, the terms "component", "module", "system", "interface", etc. are generally intended to refer to a computer-related entity, which is hardware, a combination of hardware and / or hardware, software, or software execution. For example, a component includes a process running on a processor, a processor, an object, an executable file, an execution thread, an application, or a computer. As an illustration, both an application running on a controller and a controller can be a component. One or more components and components residing within a process or execution thread can also be located on one computer, or distributed between two or more computers.

[0086] In addition, "exemplary" is used herein to mean used as an example, instance, illustration, etc., and is not necessarily advantageous. As used in this application, "or" is intended to mean an inclusive "or" rather than an exclusive "or". In addition, "a" and "an" used in this application are generally interpreted to mean "one or more", unless otherwise specified or clearly pointed to the singular form from the context. Moreover, at least one of A and B, etc. generally refers to A or B and / or both A and B. In addition, if "includes", "having", "has", "with" or its variants are used, such terms are intended to be inclusive in a manner similar to the term "comprising".

[0087] Many modifications may be made to the present disclosure without departing from the scope or spirit of the claimed subject matter. Unless otherwise specified, "first", "second", etc. do not imply temporal aspects, spatial aspects, order, etc. Instead, such terms are merely used as identifiers, names, etc. of features, elements, items, etc. For example, a first information set and a second information set generally correspond to information set A and information set B or two different or two identical information sets or the same information set.

[0088] In addition, although the present disclosure has been shown and described with respect to one or more implementations, other technical personnel in the art will be able to think of equivalent changes and modifications based on reading and understanding of this specification and the drawings. The present disclosure includes all such modifications and changes and is limited only by the scope of the appended claims. In particular, with respect to the various functions performed by the above-mentioned components (e.g., elements, resources, etc.), unless otherwise specified, the terms used to describe such components are intended to correspond to any component that performs the specified function of the described component (e.g., functionally equivalent), even if the structure is not identical to the disclosed structure. In addition, although a particular feature of the present disclosure may have been disclosed for only one of several implementations, such a feature may be combined with one or more other features of other implementations as may be desired and advantageous for any given or particular application.

Claims

1. A data storage method, It is characterized in that The method comprises: asynchronously replicating data of a storage object hosted by a first node to a replicated storage object hosted by a second node; synchronously replicating an operation targeting the storage object to the replicated storage object as a replicated operation transmitted to the second node for subsequent submission to the replicated storage object, wherein a confirmation of successful completion of the operation is generated in response to the second node indicating receipt of the replicated operation as a copy of the operation for subsequent submission; and Operations are redirected from targeting the storage object to targeting the replicated storage object based on the storage object and the replicated storage object reaching a stable state of synchronous replication.

2. The method of claim 1, wherein the copy operation is queued for subsequent submission as a background process.

3. The method according to claim 1, include: The replication operation is transmitted to the second node based on the operation being successfully performed on the storage object.

4. The method according to claim 1, include: The operations are performed on the storage objects according to a defined order.

5. The method according to claim 4, include: The copy operations are assigned sequence numbers based on the definition order.

6. The method of claim 5, wherein the sequence number is used as an indicator to the second node to perform the copy operation according to the defined order based on the sequence number.

7. The method according to claim 1, include: The timestamp of the file system modification operation is matched with the metadata of the first node.

8. The method according to claim 1, include: The timestamp of the file system modification operation is matched with the metadata of the second node.

9. The method according to claim 1, include: Data operations and metadata operations are replicated synchronously by the synchronous replication process.

10. The method of claim 9, wherein the synchronous replication process is performed after an asynchronous replication process that asynchronously replicates the data of the storage object to the replicated storage object until a cutover criterion is met.

11. The method according to claim 1, include: The modified timestamp of the storage object is synchronously copied to the replicated storage object based on the operation and the replication operation being performed in a serial manner.

12. The method according to claim 1, include: A timestamp of the copied storage object is determined to be different from a timestamp of the storage object based on the operation and the copy operation being performed out of order.

13. The method according to claim 12, include: Based on the current timestamp of the inode of the storage object being greater than the timestamp of the current operation being performed, modifying the timestamp of the storage object is suppressed.

14. A non-transitory machine-readable medium comprising instructions for performing a method, It is characterized in that When the instructions are executed by a machine, the machine: asynchronously replicating data of a storage object hosted by a first node to a replicated storage object hosted by a second node; synchronously copying an operation targeting the storage object to the replicated storage object as a replicated operation transmitted to the second node for subsequent submission to the replicated storage object, wherein a confirmation of successful completion of the operation is generated in response to the second node indicating receipt of the replicated operation as a copy of the operation for subsequent submission; as well as Operations are redirected from targeting the storage object to targeting the replicated storage object based on the storage object and the replicated storage object reaching a stable state of synchronous replication.

15. The non-transitory machine-readable medium of claim 14, wherein the copy operation is queued for subsequent submission as a background process.

16. The non-transitory machine-readable medium of claim 14, wherein the storage object comprises a plurality of volumes storing a virtual machine, and the replicated storage object comprises a plurality of replicated volumes replicating the virtual machine.

17. The non-transitory machine-readable medium of claim 16, wherein the asynchronous process and the synchronous process replicate data and operations associated with the plurality of volumes to the plurality of replicated volumes.

18. A computing device, It is characterized in that The computing device comprises: a memory including machine executable code for performing the method; and a processor coupled to the memory, the processor being configured to execute the machine executable code so that the processor: asynchronously replicating data of a storage object hosted by a first node to a replicated storage object hosted by a second node; synchronously replicating an operation targeting the storage object to the replicated storage object as a replicated operation transmitted to the second node for subsequent submission to the replicated storage object, wherein a confirmation of successful completion of the operation is generated in response to the second node indicating receipt of the replicated operation as a copy of the operation for subsequent submission; and Operations are redirected from targeting the storage object to targeting the replicated storage object based on the storage object and the replicated storage object reaching a stable state of synchronous replication.

19. The computing device of claim 18, wherein the copy operation is queued for subsequent submission as a background process.

20. The computing device of claim 18, wherein the machine executable code causes the processor to: A timestamp of a file system modification operation is matched with metadata of the first node and the second node.

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