Automatic capacity expansion method, device and equipment for LVM2 Qcow2 disk, medium and program product
By introducing an automatic capacity expansion mechanism in QEMU, using the arithmetic sequence threshold quota method and the isometric sequence space allocation method, the problem of low capacity expansion efficiency of LVM2 Qcow2 disks is solved, and efficient utilization and automatic capacity expansion of storage resources in the virtual machine are realized.
Patent Information
- Application Number
- CN202411330319.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-24
- Publication Date
- 2025-02-07
AI Technical Summary
The existing LVM2 Qcow2 disk expansion policy has problems such as low disk utilization, low capacity expansion efficiency and multiple capacity expansion, especially when the virtual machine continues to write data.
The automatic expansion method based on QEMU is adopted, and the storage space is automatically expanded when writing data by adding a storage space detection mechanism. The specific implementation includes arithmetic sequence threshold quota method and isometric sequence space allocation method, and dynamically adjusts the storage space threshold and allocation value to adapt to disk usage characteristics.
It realizes automatic expansion of LVM2 Qcow2 disks inside the virtual machine, ensures uninterrupted operation of the virtual machine, improves storage resource utilization and capacity expansion efficiency, and reduces the overhead of storage devices.
Smart Images
Figure CN119396518A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of storage system management, and in particular to an automatic capacity expansion method, device, equipment, medium and program product of an LVM2 Qcow2 disk. Background Art
[0002] The cloud virtualization platform uses Libvirt as the virtualization Hypervisor, and QEMU as the driver of Libvirt to implement virtualization management of the virtualization platform. The virtualization platform provides basic cloud disk functions. The created cloud disk can be used as both a system disk and a data disk for virtual machines. The LVM2 logical volume LV is the physical disk when the cloud disk is created. The LV is in the format of a Qcow2 disk and is used by the virtual machine.
[0003] For common expansion strategies for LVM2 Qcow2, see Figure 1 : Start the daemon process, monitor the Libvirt virtual machine disk IO space shortage event, and expand the disk with a fixed size granularity. The disk utilization rate under this strategy is low, which wastes storage resources; each fixed granularity expansion does not consider the disk usage characteristics, and the expansion efficiency is low; when writing to the disk continuously and the space is insufficient, the disk needs to be expanded multiple times. Summary of the invention
[0004] Purpose of the invention: A method, device, equipment, medium and program product for realizing automatic expansion of LVM2 Qcow2 disk based on QEMU are proposed, so as to realize automatic expansion of LVM2 Qcow2 disk by continuous writing inside virtual machine, and uninterrupted operation of virtual machine during disk expansion; automatic expansion of disk by using LVM2 Qcow2 disk as the destination disk for cloud hard disk cloning; and functions such as deleting cloud hard disk snapshot volume and automatic expansion of base volume LVM2 Qcow2 disk are realized.
[0005] A first aspect of the present invention provides an automatic capacity expansion method for an LVM2 Qcow2 disk. When QEMU-KVM writes data to the Qcow2 disk of LVM2, a storage space detection mechanism is added to automatically expand the storage space when writing data.
[0006] The storage space detection mechanism uses an arithmetic progression threshold quota method to check the storage space: One tenth of the physical capacity of the LVM2 Qcow2 disk is used as the starting quota value of the threshold, and the threshold is decreased in an arithmetic progression, with a tolerance of one percent of the physical capacity of the LVM2 Qcow2. If the capacity is not automatically expanded within the first predetermined period, the threshold is restored to one tenth of the physical capacity of the disk.
[0007] The process of automatically expanding storage space when writing data specifically includes: The storage space is allocated using the geometric progression space allocation method, with one-tenth of the physical capacity of the LVM2 Qcow2 disk as the starting value for space allocation, and the space is increased in a geometric progression with a common ratio of 1.1; If the number of times the geometric sequence space allocation method allocates storage space within the second predetermined time is equal to three times, the logical value of the third expansion to the LVM2 Qcow2 disk; If the capacity is no longer automatically expanded within the first predetermined period, the starting value of the space allocation is restored to one tenth of the physical capacity of the disk; when the total expanded capacity is greater than the logical value of the LVM2 Qcow2 disk, the capacity is no longer automatically expanded and insufficient storage space is reported.
[0008] Specifically, the automatic expansion method of the LVM2 Qcow2 disk includes the following steps: Add access rights for LVM2 logical volume management; Get access to LVM2 devices and obtain the real-time disk physical capacity of LVM2 Qcow2; When writing data to an LVM2 Qcow2 disk, the disk capacity is checked, the storage space is checked according to the arithmetic progression threshold quota method, and a decision is made whether to allocate the storage space according to the geometric progression space allocation method; If the number of allocations by the geometric sequence space allocation method is equal to three times within 2 minutes, the logical value of the third expansion to the LVM2 Qcow2 disk; If the capacity is not automatically expanded within 5 minutes, the threshold is restored to one tenth of the physical capacity of the LVM2 Qcow2 disk, and the starting value of space allocation is restored to one tenth of the physical capacity of the LVM2 Qcow2 disk; When the total capacity of the expansion is greater than the logical value of the LVM2 Qcow2 disk, the capacity is no longer expanded automatically and insufficient storage space is reported.
[0009] In a further embodiment, the process of checking the storage space according to the arithmetic progression threshold quota method specifically includes: taking one tenth of the physical capacity of the LVM2 Qcow2 disk as the starting quota value of the threshold, decreasing the threshold in the form of an arithmetic progression, and the tolerance is one percent of the physical capacity of the LVM2 Qcow2 disk.
[0010] In a further embodiment, the process of allocating storage space using the geometric progression space allocation method specifically includes: taking one tenth of the physical capacity of the LVM2 Qcow2 disk as the starting value of space allocation, and increasing the space allocation value in the form of a geometric progression, with a common ratio of 1.1.
[0011] A second aspect of the present invention provides an automatic capacity expansion device for LVM2 Qcow2 disks, which includes three parts: a control resource module, a QEMU calling module, and an allocation strategy execution module.
[0012] The control resource module is used to grant access rights to the LVM2 logical volume management. The QEMU call module is used to obtain access rights to the LVM2 device. The allocation strategy execution module is used to obtain the real-time disk physical capacity of the LVM2 Qcow2 and decide whether to execute the allocation and expansion of the storage space. The allocation strategy execution module can automatically execute the automatic expansion method of the LVM2Qcow2 disk as described in the first aspect.
[0013] According to a third aspect of the present invention, an electronic device is provided, the electronic device comprising a processor and a memory storing computer program instructions. When the processor executes the computer program instructions, the automatic capacity expansion method of the LVM2Qcow2 disk as described in the first aspect is implemented.
[0014] In a fourth aspect of the present invention, a computer-readable storage medium is provided, wherein at least one executable instruction is stored in the storage medium. When the executable instruction is executed on an electronic device, the electronic device executes the automatic capacity expansion method of the LVM2 Qcow2 disk as described in the first aspect.
[0015] According to a fifth aspect of the present invention, a computer program product is provided. The computer program product includes a computer program. When the computer program is executed by a processor, the automatic capacity expansion method of the LVM2 Qcow2 disk as described in the first aspect is implemented.
[0016] Compared with the prior art, the present invention has at least the following beneficial effects: 1. For QEMU virtual machines using LVM2's QCOW2 disk, when the logical volume is automatically expanded, the virtual machine does not restart and the business runs uninterrupted, ensuring the integrity and consistency of the data inside the virtual machine.
[0017] 2. The arithmetic progression threshold quota method is used to check storage space. The disk space check adopts a reverse dynamic adjustment strategy. According to the frequency of disk use, the threshold is reduced each time the check is performed to improve the efficiency of storage space inspection.
[0018] 3. The storage space is allocated by the geometric sequence space allocation method. The disk space allocation adopts a positive dynamic adjustment strategy. According to the frequency of disk use, the space allocation value is increased each time to improve the storage space allocation efficiency. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Figure 1 This is a schematic diagram of the existing LVM2 Qcow2 expansion strategy.
[0020] Figure 2 It is a schematic diagram of implementing capacity expansion of LVM2 Qcow2 disk based on QEMU in an embodiment.
[0021] Figure 3 It is a detailed flow chart of implementing capacity expansion of LVM2 Qcow2 disk based on QEMU in the embodiment.
[0022] Figure 4 It is a schematic diagram of the structure of the automatic capacity expansion device of the LVM2 Qcow2 disk in the embodiment. DETAILED DESCRIPTION
[0023] In the following description, a large number of specific details are provided to provide a more thorough understanding of the present invention. However, it is apparent to those skilled in the art that the present invention can be implemented without one or more of these details. In other examples, in order to avoid confusion with the present invention, some technical features known in the art are not described.
[0024] In order to solve the shortcomings of the existing LVM2 Qcow2 expansion strategy, this embodiment provides a method for automatically expanding the capacity of LVM2 Qcow2 disk based on QEMU. When QEMU-KVM writes data to the Qcow2 disk of LVM2, a storage space detection mechanism is added to automatically expand the storage space when writing data: The arithmetic progression threshold quota method is used to check storage space: one tenth of the physical capacity of the LVM2 Qcow2 disk is used as the starting quota value of the threshold, and the threshold is decreased in an arithmetic progression. The tolerance is one percent of the physical capacity of the LVM2 Qcow2. If the capacity is not automatically expanded within 5 minutes, the threshold is restored to one tenth of the physical capacity of the disk.
[0025] Allocate storage space using the geometric progression space allocation method: use one-tenth of the physical capacity of the LVM2 Qcow2 disk as the starting value for space allocation, and increase the space in a geometric progression with a common ratio of 1.1; if the geometric progression space allocation method allocates storage space three times within 2 minutes, the capacity is expanded to the logical value of the LVM2 Qcow2 disk for the third time; if the capacity is no longer automatically expanded within 5 minutes, the starting value of space allocation is restored to one-tenth of the physical capacity of the disk; when the total expanded capacity is greater than the logical value of the LVM2Qcow2 disk, the capacity is no longer automatically expanded, and insufficient storage space is reported.
[0026] Arithmetic progression threshold quota method threshold and geometric progression space allocation method space allocation, when expanding for the first time, the threshold and initial space allocation value are calculated based on the initial physical capacity of the disk. Arithmetic progression threshold quota method and geometric progression space allocation method, when checking disk space, the current check time is recorded each time, and compared with the last check time. If the disk is expanded again within 5 minutes, the calculation of the threshold and initial space allocation value are based on the first calculation of the disk physical capacity within 5 minutes; if it exceeds 5 minutes, the disk physical capacity is re-checked and calculated. To calculate the disk threshold and physical capacity, add two members vg and lv in the structure BDRVRawState to record the volume group and logical volume to which the LVM2 Qcow2 disk belongs. The calculation is performed by the lvm2_run method provided by lvm2cmd.h. When the capacity is expanded, the cmd parameter is lvextend --noudevsync --size size vg / lv, where size is the value to be expanded, vg is the logical volume group name, and lv is the logical volume name. When calculating the physical capacity, the cmd parameter is lvs –noheadings -o lv_size vg / lv, where vg is the logical volume group name, and lv is the logical volume name.
[0027] Based on the contents disclosed in the above embodiments, this embodiment discloses details of some steps of the automatic expansion method: Step 1: Libvirt cgroup control resource module adds access rights to LVM2 logical volume management.
[0028] Step 2: QEMU QemuSeccompSyscall obtains access to the LVM2 device, and the virtual machine started by QEMU-KVM obtains the real disk physical capacity of LVM2 Qcow2.
[0029] Step 3: When writing data to the LVM2 Qcow2 disk, check the disk capacity, check the storage space according to the arithmetic progression threshold quota method, and decide whether to allocate the storage space using the geometric progression space allocation method.
[0030] Step 4: Check the storage space using the arithmetic progression threshold quota method. Take one-tenth of the physical capacity of the LVM2 Qcow2 disk as the starting quota value of the threshold, and decrease the threshold in an arithmetic progression. The tolerance is one percent of the physical capacity of the LVM2 Qcow2 disk.
[0031] Step 5: Allocate storage space using the geometric progression space allocation method. Take one-tenth of the physical capacity of the LVM2 Qcow2 disk as the starting value for space allocation, and increase the space allocation value in the form of a geometric progression. The common ratio is 1.1.
[0032] Step 6: If the geometric sequence space allocation method allocates three times within two minutes, the capacity is expanded to the logical value of the LVM2 Qcow2 disk for the third time.
[0033] Step 7: If the capacity is not automatically expanded within five minutes, the threshold is restored to one tenth of the physical capacity of the LVM2 Qcow2 disk, and the starting value of the space allocation is restored to one tenth of the physical capacity of the LVM2 Qcow2 disk.
[0034] Step 8: When the total capacity of the expansion is greater than the logical value of the LVM2 Qcow2 disk, the capacity is no longer expanded automatically and insufficient storage space is reported.
[0035] The following is a set of feasible commands for implementing the automatic expansion method of LVM2 Qcow2 disk based on QEMU. The following commands are all implemented on the Linux system.
[0036] S101: Upgrade qemu to realize automatic expansion of LVM2 Qcow2 disks.
[0037] rpm -ivh qemu-kvm-8.2.4-1.ctl3.x86_64.rpm S102: Create a 1 GB LVM2 volume in VG vg_stor.
[0038] lvcreate -L 1G -n lv_stor vg_stor S103: Create a 10G LVM2 Qcow2 volume lv_stor based on the already created LVM2 logical volume lv_stor.
[0039] qemu-img create -f qcow2 / dev / vg_stor / lv_stor 10G S104: qemu-img convert clones the cloud hard disk.
[0040] Create a 2G source disk and use the LVM2 Qcow2 disk as the destination disk during qemu-img convert. If the source disk is larger than the LVM2 Qcow2 physical space and smaller than the LVM2 Qcow2 logical space, the LVM2 Qcow2 disk will be automatically expanded.
[0041] lvcreate -L 2G -n lv_source vg_stor qemu-img convert -p -n -t none -f raw -O qcow2 / dev / vg_stor / lv_source / dev / vg_stor / lv_stor S105: qemu-img commit deletes the cloud disk snapshot volume.
[0042] qemu-img commit merges snapshots into the backing files of the LVM2 Qcow2 disk, and the LVM2 Qcow2 disk is automatically expanded.
[0043] lvcreate -L 10G -n lv_stor_sn vg_stor qemu-img create -f qcow2 -b / dev / clvm-az1-store1 / lv_stor / dev / clvm-az1-store1 / lv_stor_sn -F qcow2 qemu-img commit / dev / clvm-az1-store1 / lv_stor_sn S106: The virtual machine uses the LVM2 Qcow2 disk as the system disk.
[0044] The virtual machine uses the LVM2 Qcow2 disk as the system disk. The DD inside the virtual machine writes data to the disk, and the LVM2Qcow2 disk is automatically expanded.
[0045] dd if= / dev / zero of= / data bs=1M count=2048 S107: The virtual machine uses an LVM2 Qcow2 disk as a data disk.
[0046] The virtual machine uses the LVM2 Qcow2 disk as the data disk. The DD inside the virtual machine writes data to the disk, and the LVM2Qcow2 disk is automatically expanded.
[0047] dd if= / dev / zero of= / dev / sdb bs=1M count=2048 See Figure 4 This embodiment discloses an automatic capacity expansion device 900 for an LVM2 Qcow2 disk. The device includes three parts: a control resource module 901, a QEMU calling module 902, and an allocation strategy execution module 903.
[0048] The control resource module 901 is used to grant access rights to the LVM2 logical volume management. The QEMU call module 902 is used to obtain access rights to the LVM2 device. The allocation strategy execution module 903 is used to obtain the real-time disk physical capacity of the LVM2 Qcow2 and determine whether to perform the allocation and expansion of the storage space. The allocation strategy execution module 903 can automatically execute the automatic expansion method of the LVM2 Qcow2 disk disclosed in the above embodiment.
[0049] Specifically, the allocation strategy execution module 903 is composed of a storage space checking unit and a storage space allocation unit. The storage space checking unit uses one tenth of the physical capacity of the LVM2 Qcow2 disk as the starting quota value of the threshold, decreases the threshold in an arithmetic progression, and uses one percent of the physical capacity of the LVM2 Qcow2 as the tolerance; if the capacity is no longer automatically expanded within the first predetermined time, the threshold is restored to one tenth of the physical capacity of the disk.
[0050] The storage space allocation unit uses the geometric progression space allocation method to allocate storage space, with one-tenth of the physical capacity of the LVM2 Qcow2 disk as the starting value for space allocation, and increases the space in a geometric progression with a common ratio of 1.1. If the geometric progression space allocation method allocates three times within 2 minutes, the third capacity is expanded to the logical value of the LVM2 Qcow2 disk. If there is no automatic capacity expansion within 5 minutes, the threshold is restored to one-tenth of the physical capacity of the LVM2 Qcow2 disk, and the starting value of space allocation is restored to one-tenth of the physical capacity of the LVM2 Qcow2 disk. When the total capacity of the expansion is greater than the logical value of the LVM2 Qcow2 disk, the capacity is no longer automatically expanded, and insufficient storage space is reported.
[0051] In practical applications, a set of executable instructions for implementing the automatic expansion method of LVM2 Qcow2 disk based on QEMU can be written into a storage medium and run on an electronic device. The executable instructions are as follows: rpm -ivh qemu-kvm-8.2.4-1.ctl3.x86_64.rpm #Upgrade qemu to achieve automatic expansion of LVM2 Qcow2 disks lvcreate -L 1G -n lv_stor vg_stor #Create a 1G LVM2 logical volume in VG vg_stor qemu-img create -f qcow2 / dev / vg_stor / lv_stor 10G #Create a 10G LVM2 Qcow2 volume lv_stor based on the already created LVM2 logical volume lv_stor lvcreate -L 2G -n lv_source vg_stor #Create a 2G source disk qemu-img convert -p -n -t none -f raw -O qcow2 / dev / vg_stor / lv_source / dev / vg_stor / lv_stor # When qemu-img convert is used, the LVM2 Qcow2 disk is used as the destination disk. When the source disk is larger than the LVM2 Qcow2 physical space and smaller than the LVM2 Qcow2 logical space, the LVM2 Qcow2 disk is automatically expanded. lvcreate -L 10G -n lv_stor_sn vg_stor qemu-img create -f qcow2 -b / dev / clvm-az1-store1 / lv_stor / dev / clvm-az1-store1 / lv_stor_sn -F qcow2 qemu-img commit / dev / clvm-az1-store1 / lv_stor_sn # qemu-img commit merges snapshots to backing files, which are LVM2 Qcow2 disks. LVM2 Qcow2 disks are automatically expanded. dd if= / dev / zero of= / data bs=1M count=2048 #The virtual machine uses the LVM2 Qcow2 disk as the system disk. The DD inside the virtual machine writes data to the disk. The LVM2 Qcow2 disk automatically expands. dd if= / dev / zero of= / dev / sdb bs=1M count=2048 #The virtual machine uses the LVM2 Qcow2 disk as the data disk. The DD inside the virtual machine writes data to the disk. The LVM2 Qcow2 disk automatically expands. More specific examples of computer-readable storage media mentioned in this embodiment may include, but are not limited to: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), an erasable programmable read-only memory (EPROM or flash memory), an optical storage device, a magnetic storage device, or any suitable combination of the above. Computer-readable storage media may include a data signal propagated in a baseband or as part of a carrier wave, wherein a readable program code is carried. Such propagated data signals may take a variety of forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the above. The readable signal medium may also be any readable medium other than a readable storage medium, which may send, propagate, or transmit a program for use by or in conjunction with an instruction execution system, device, or device.
[0052] The above embodiment proposes a method for automatically expanding LVM2 Qcow2 disks based on QEMU. QEMU implements automatic expansion of LVM2 Qcow2 disks, giving full play to the space-saving characteristics of Qcow2 disks, improving the utilization rate of storage devices, and reducing the cost of IT infrastructure. The automatic expansion solution can achieve: Take advantage of the space-saving features of LVM2 Qcow2 disks to reduce storage device overhead; Improve the overall performance of the system and ensure the integrity and consistency of data within the virtual machine; Reduce system overhead, no longer need a daemon process to monitor the IO events of the virtual machine.
[0053] As described above, although the present invention has been shown and described with reference to specific preferred embodiments, it should not be construed as limiting the present invention itself. Various changes in form and details may be made without departing from the spirit and scope of the present invention as defined in the appended claims.
Claims
1. A method for automatically expanding LVM2 Qcow2 disks, characterized in that: When QEMU-KVM writes data to the Qcow2 disk of LVM2, a storage space detection mechanism is added to automatically expand the storage space when writing data.
2. The automatic capacity expansion method according to claim 1, characterized in that: The storage space detection mechanism uses an arithmetic progression threshold quota method to check the storage space: One tenth of the physical capacity of the LVM2 Qcow2 disk is used as the starting quota value of the threshold, and the threshold is decreased in an arithmetic progression, with a tolerance of one percent of the physical capacity of the LVM2 Qcow2. If the capacity is not automatically expanded within the first predetermined period, the threshold is restored to one tenth of the physical capacity of the disk.
3. The automatic capacity expansion method according to claim 1, characterized in that: The automatic expansion of storage space when writing data specifically includes: The storage space is allocated using the geometric progression space allocation method, with one-tenth of the physical capacity of the LVM2 Qcow2 disk as the starting value for space allocation, and the space is increased in a geometric progression with a common ratio of 1.1; If the number of times the geometric sequence space allocation method allocates storage space within the second predetermined time is equal to three times, the logical value of the third expansion to the LVM2 Qcow2 disk; If the capacity is no longer automatically expanded within the first predetermined period, the starting value of the space allocation is restored to one tenth of the physical capacity of the disk; when the total expanded capacity is greater than the logical value of the LVM2 Qcow2 disk, the capacity is no longer automatically expanded and insufficient storage space is reported.
4. A method for automatically expanding LVM2 Qcow2 disk, characterized in that: The steps include: Add access rights for LVM2 logical volume management; Get access to LVM2 devices and obtain the real-time disk physical capacity of LVM2 Qcow2; When writing data to an LVM2 Qcow2 disk, the disk capacity is checked, the storage space is checked according to the arithmetic progression threshold quota method, and a decision is made whether to allocate the storage space according to the geometric progression space allocation method; If the number of allocations by the geometric sequence space allocation method is equal to three times within 2 minutes, the third expansion is to the logical value of the LVM2 Qcow2 disk; If the capacity is not automatically expanded within 5 minutes, the threshold is restored to one tenth of the physical capacity of the LVM2 Qcow2 disk, and the starting value of space allocation is restored to one tenth of the physical capacity of the LVM2 Qcow2 disk; When the total capacity of the expansion is greater than the logical value of the LVM2 Qcow2 disk, the capacity is no longer expanded automatically and insufficient storage space is reported.
5. The automatic capacity expansion method according to claim 4, characterized in that: The checking of storage space according to the arithmetic progression threshold quota method specifically includes: The starting quota value of the threshold is one tenth of the physical capacity of the LVM2 Qcow2 disk, and the threshold is decreased in an arithmetic progression. The tolerance is one percent of the physical capacity of the LVM2 Qcow2 disk.
6. The automatic capacity expansion method according to claim 4, characterized in that: The geometric progression space allocation method allocates storage space, specifically including: The starting value for space allocation is one-tenth of the physical capacity of the LVM2 Qcow2 disk, and the space allocation value is increased in a geometric progression with a common ratio of 1.
1.
7. An automatic capacity expansion device for LVM2 Qcow2 disk, characterized in that: include: Control resource module, used to grant access rights to LVM2 logical volume management; QEMU calls the module to gain access to LVM2 devices; The allocation strategy execution module is used to obtain the real-time physical capacity of the LVM2 Qcow2 disk and decide whether to allocate and expand the storage space; The allocation strategy execution module can automatically execute the automatic capacity expansion method of the LVM2 Qcow2 disk according to any one of claims 1 to 6.
8. An electronic device, characterized in that: The device comprises: a processor and a memory storing computer program instructions; when the processor executes the computer program instructions, the automatic capacity expansion method of the LVM2Qcow2 disk according to any one of claims 1 to 6 is implemented.
9. A computer-readable storage medium, characterized in that: At least one executable instruction is stored in the storage medium. When the executable instruction is executed on the electronic device, the electronic device executes the automatic capacity expansion method of the LVM2 Qcow2 disk according to any one of claims 1 to 6.
10. A computer program product, characterized in that The computer program product comprises a computer program, and when the computer program is executed by a processor, the method for automatically expanding the LVM2 Qcow2 disk according to any one of claims 1 to 6 is implemented.