535 results about "Dirty data" patented technology

A system, method, and computer program product for a lease-based timeout scheme that addresses fencing's shortcomings. Unlike fencing, this scheme (or protocol) enables an isolated computer to realize it is disconnected from the distributed system and write its dirty data out to storage before its locks are stolen. In accordance with the invention, data consistency during a partition in a distributed system is ensured by establishing a lease based protocol between in the distributed system wherein a client can hold a lease with a server. The lease represents a contract between a client and a server in which the server promises to respect the client for a period of time. The server respects the contract even when it detects a partition between the client and itself.

An apparatus, system, and method are disclosed for satisfying storage requests while destaging cached data. A monitor module samples a destage rate for a nonvolatile solid-state cache, a total cache write rate for the cache, and a dirtied data rate. The dirtied data rate comprises a rate at which write operations increase an amount of dirty data in the cache. A target module determines a target cache write rate for the cache based on the destage rate, the total cache write rate, and the dirtied data rate to target a destage write ratio. The destage write ratio comprises a predetermined ratio between the dirtied data rate and the destage rate. A rate enforcement module enforces the target cache write rate such that the total cache write rate satisfies the target cache write rate.

A power saving cache and a method of operating a power saving cache. The power saving cache includes circuitry to dynamically reduce the logical size of the cache in order to save power. Preferably, a method is used to determine optimal cache size for balancing power and performance, using a variety of combinable hardware and software techniques. Also, in a preferred embodiment, steps are used for maintaining coherency during cache resizing, including the handling of modified (“dirty”) data in the cache, and steps are provided for partitioning a cache in one of several way to provide an appropriate configuration and granularity when resizing.

A method and system directed to improve effectiveness and efficiency of cache and data management by differentiating data based on certain attributes associated with the data and reducing the bottleneck to storage. The data-aware cache differentiates and manages data using a state machine having certain states. The data-aware cache may use data pattern and traffic statistics to retain frequently used data in cache longer by transitioning it into Sticky or StickyDirty states. The data-aware cache may also use content or application related attributes to differentiate and retain certain data in cache longer. Further, the data-aware cache may provide cache status and statistics information to a data-aware data flow manager, thus assisting data-aware data flow manager to determine which data to cache and which data to pipe directly through, or to switch cache policies dynamically, thus avoiding some of the overhead associated with caches. The data-aware cache may also place clean and dirty data in separate states, enabling more efficient cache mirroring and flush, thus improve system reliability and performance.

An I/O processor determines whether or not the amount of dirty data on a cache memory exceeds a threshold value and, if the determination is that this threshold value has been exceeded, writes a portion of the dirty data of the cache memory to a storage device. If a power source monitoring and control unit detects a voltage abnormality of the supplied power, the power monitoring and control unit maintains supply of power using power from a battery, so that a processor receives supply of power from the battery and saves the dirty data stored on the cache memory to a non-volatile memory.

The invention discloses a cache management method for a solid-state disc. The method comprises the following implement steps that a page cache, a replace block module, a new page linked list, a physical block chain list and a physical page state list are established; an input and output (IO) request from a host is received and is executed through the page cache, when a writing request is executed, if the page cache is missed, and the page cache has no spare space, a block replace process of the solid-state disc is executed, namely an 'effective' page space in the page cache is preferential released; when the number of 'effective' pages in the page cache is zero, a candidate replace block with the largest failure ratio in a rear half physical block of the physical block chain list is selected to serve as a replace block, and the replace block cache is utilized to execute a replace writing process. The cache management method for the solid-state disc can effectively use a limited cache space and increase hit rate of the cache, enables a block written in a flash medium to comprise as many dirty data pages as possible and as few effective data pages as possible to reduce erasure operation and page copy operations and sequential rubbish recovery caused by the dirty data pages. The cache management method for the solid-state disc is easy to operate.

A system and method for updating dirty data of designated raw device is applied in Linux system. A format of a command parameter for updating the dirty data of the designated raw device is determined, to obtain the command parameter with the correct format and transmit it into the Kernel of the Linux system. Then, a data structure of the designated raw device is sought based on the command parameter, to obtain a fast search tree of the designated raw device. Finally, all dirty data pages of the designated raw device are found by the fast search tree, and then are updated into a magnetic disk in a synchronous or asynchronous manner. Therefore, the dirty data of an individual raw device can be updated and written into the magnetic disk without interrupting the normal operation of the system, hereby ensuring secure, convenient, and highly efficient update of the dirty data.

A method and apparatus physically partitions clean and dirty cache lines into separate memory partitions, such as one or more banks, so that during low power operation, a cache memory controller reduces power consumption of the cache memory containing the clean only data. The cache memory controller controls a refresh operation so that a data refresh does not occur for the clean data only banks or the refresh rate is reduced for the clean data only banks. Partitions that store dirty data can also store clean data; however, other partitions are designated for storing only clean data so that the partitions can have their refresh rate reduced or refresh stopped for periods of time. When multiple DRAM dies or packages are employed, the partition can occur on a die or package level as opposed to a bank level within a die.

One embodiment of the present invention sets forth a technique for processing commands received by an intermediary cache from one or more clients. The technique involves receiving a first write command from an arbiter unit, where the first write command specifies a first memory address, determining that a first cache line related to a set of cache lines included in the intermediary cache is associated with the first memory address, causing data associated with the first write command to be written into the first cache line, and marking the first cache line as dirty. The technique further involves determining whether a total number of cache lines marked as dirty in the set of cache lines is less than, equal to, or greater than a first threshold value, and: not transmitting a dirty data notification to the frame buffer logic when the total number is less than the threshold value, or transmitting a dirty data notification to the frame buffer logic when the total number is equal to or greater than the first threshold value.

A method and system for implementing coalescing write IOs for an electronic and computerized system is disclosed. The electronic and computerized system has a buffer cache storing data blocks waiting for being written into a disk of the electronic and computerized system. Dirty data blocks with consecutive data block addresses in the buffer cache are coalesced and written to the disk together. Thus, the disk head movements for performing the write IOs are significantly reduced, thereby allowing the electronic and computerized system to maintain a high IO throughput and high peak performance with fewer disks.

A method for recovering dirty write cache data after controller power loss or failure from one of two independently battery backed up and mirrored write caches. Two independent controllers jointly operate with a permanent data storage system. Each controller has a write cache that is a mirror of the write cache in the other controller. The primary controller resets a power down flag stored each write cache upon proper shutdown. The primary controller further increments and stores a configuration sequence number into each write cache upon proper shutdown. If a primary controller powers up and identifies that the write cache was not properly shutdown due to the state of the power down flag, it flushes the dirty data in the write cache only if the configuration sequence number contained in the write cache is the same as the configuration sequence number contained in the primary controller. If the configuration sequence number in the primary controller is higher than the configuration sequence number in the write cache, the dirty data was previously flushed to permanent data storage with the other write cache.

An embodiment of the invention provides a data update method for a Key-Value storage system via distributed key values. Through replication of nodes requiring update, father nodes, ancestor nodes, and root nodes to a buffer layer of the Key-Value storage system, modification of key values and contents of the nodes requiring update, the father nodes, and the ancestor nodes, and modification of the contents of the root nodes, the nodes are made different from original nodes in the storage layer. The method is characterized in that, the nodes requiring update, the father nodes, and the ancestor nodes are first stored in the storage layer, and then the root nodes are stored in a key value pair system. Since the nodes requiring update in the buffer layer are stored in the storage layer prior to storage of the root nodes in the buffer layer in the storage layer, reading operation in the storage process of the nodes requiring update does not enable reading of the nodes requiring update, thereby preventing reading of dirty data. The invention also provides a corresponding method for reading index nodes and a server.

The invention provides a cached data disk brushing method and device. The cached data disk brushing method is applied to a storage system. The storage system comprises a controller, a disk and an SSD, wherein the SSD serves as a cache of the disk. The cached data disk brushing method is executed by the controller and comprises the steps of sending a cached data reading request to the SSD, wherein the cached data reading request includes identifications of dirty data blocks of M disks to be brushed; receiving cached data reading request response sent by the SSD, wherein the cached data reading request response includes cached data of dirty data blocks of N disks to be brushed, and the M is greater than or equal to the N; determining LBA respectively corresponding to the dirty data blocks of the N disks according to the corresponding relation of the identifications of the dirty data blocks and the LBA; sequentially storing the cached data of the dirty data blocks of the N disks in the disk according to the LBA respectively corresponding to the dirty data blocks of the N disks and in an LBA sequence from small to large.

The invention aims to provide a method and equipment for synchronization of a distributed caching system. The method comprises the steps of acquiring a distribution list from main cluster configuration service equipment, wherein the distribution list comprises information of the main cluster data service equipment which requires maintenance synchronization; based on the distribution list, acquiring a data log from the main cluster data service equipment, and generating synchronization task information based on the data log; and transmitting the synchronization task information to backup cluster data service equipment for synchronization, thereby continuously synchronizing the particular state of the data service equipment before shutdown to taking-over data service equipment when shutdown of the main cluster data service equipment or shutdown of the integral main cluster occurs, and preventing dirty data or data loss accordingly.

The invention discloses a disk array caching method for a virtual SSD and an SSD isomerous mirror image. The disk array caching method comprises the steps that a disk is logically divided into two parts, wherein the upper half part forms an RAID0 or RAID5 structure to serve as the virtual SSD so as to back up dirty data in a real SSD, the virtual SSD is in a log writing mode, a ram writing cache is set, and the lower half portion is assembled to be of different RAID structures according to needs of users, and is used as a data array so as to store cold data; an address mapping Hash locating table between a data disk and the cache of the real SSD is built; a timer is set so as to regularly write data cached in the ram writing cache of the virtual SSD into the virtual SSD; a request from an upper layer file system is received; for a reading request, when the reading request is not hit in the real SSD, data are read from the data array. The disk array caching method gives consideration to performance, reliability and cost.

The invention provides a memory system, and a method and a system for controlling service quality of the memory system. The method for controlling the service quality of the memory system comprises the following steps: collecting processing capability information of hard discs in the memory system, and obtaining processing capabilities of the hard discs through the processing capability information; dividing a cache into a plurality of levels according to the processing capabilities of the hard discs, wherein the cache in each level corresponds to one or more hard discs in the memory system, and the page quota of the cache in each level is pre-allocated according to the processing capability information of one or more hard discs corresponding to the cache in each level; and for the cache of a level in which dirty data reach a preset proportion, writing data in the cache of the level into the hard discs corresponding to the cache of the level. The system for controlling the service quality of the memory system comprises a collecting module, a first dividing module and a disc-writing module; and the memory system comprises a host, a cache and the system for controlling the service quality of the memory system. The preemption of page resources in the cache is avoided.

The embodiment of the invention provides a method for managing a hybrid cache. The hybrid cache comprises an RAM and a solid state memory SSD. The method comprises the steps that a second queue and a third queue are generated, wherein the second queue is used for managing hot clean data blocks in the RAM; the third queue is used for managing dirty data blocks in the RAM; the sum of the length of the second queue and the length of the third queue is unchanged; the elimination probability of the second queue is higher than that of the third queue, the length of the second queue dynamically changes along with the elimination operation executed on the second queue, and the length of the third queue dynamically changes along with the elimination operation executed on the third queue; whether the access frequency of data blocks eliminated from the second queue or the third queue exceeds an access frequency threshold value or not is determined; if yes, the data blocks are judged as long-term hot data blocks, the eliminated data blocks are managed by using a fifth queue and are written in the SSD, and the fifth queue is used for managing the data blocks in the SSD.

The invention provides a data synchronizing method and a data synchronizing system. The data synchronizing method comprises the steps that an auxiliary station acquires updated data information of a master station and utilizes the updated data information to synchronize data of a storage layer of the auxiliary station; and then data in a buffer memory layer of the auxiliary station is synchronized according to data synchronizing information of the storage layer of the auxiliary station. According to the data synchronizing method and the data synchronizing system, reliability of data in an auxiliary computer room is guaranteed, and generation of dirty data is avoided.