CN105573813A - Continuous snapshooting method and device of virtual machine - Google Patents

Abstract

The present invention provides a virtual machine continuous snapshot method and device. The virtual machine continuous snapshot method includes: stopping the virtual machine; updating the value of the second bitmap information of each page according to the value of the first bitmap information of each page in the virtual machine ; Initialize the value of the first bitmap information of each page in the virtual machine; resume the operation of the virtual machine; determine in turn whether the value of the second bitmap information of each page in the virtual machine is the first preset value, and set the second Each page whose value of the bitmap information is the first preset value is saved to the cache area. The virtual machine continuous snapshot device only needs to operate the bitmap information of each page during the virtual machine shutdown process, and the time required for this process is very short, which shortens the virtual machine downtime during the snapshot process. Each saved page is saved as a snapshot, and only the unsaved pages are saved, which greatly shortens the time for a snapshot of the virtual machine and reduces the impact of the snapshot process on the performance of the virtual machine.

Description

Method and device for continuous snapshot of virtual machine

technical field

The invention relates to the technical field of computers, in particular to a method and device for continuous snapshots of a virtual machine.

Background technique

Virtualization technology can effectively integrate and utilize computer resources, so it has become a key supporting computing in the field of cloud computing. In order to provide continuous and highly available cloud services, the data and state in the virtual machine need to meet the requirements of reliability and security, thus introducing the snapshot technology. The snapshot technology can save the complete state of the virtual machine during running, including the disk state, memory state and device state of the virtual machine, such as CPU, network, etc. Machine data and status.

At present, when a virtual machine takes a snapshot of the memory state, it mainly uses downtime copying. Shutdown copy is to suspend the virtual machine when taking continuous snapshots of the virtual machine, and then resume the virtual machine after all the memory data is saved, so as to ensure that the data of each page in the virtual machine memory is complete during this snapshot, and has not been deleted. Revise.

However, downtime copying makes the downtime of the virtual machine very long during each snapshot, which affects the performance of the virtual machine.

Contents of the invention

The present invention provides a virtual machine continuous snapshot method and device, which are used to solve the problem in the prior art that the virtual machine continuous snapshot method makes the virtual machine down for a long time and affects the performance of the virtual machine.

The present invention provides a virtual machine continuous snapshot method, including:

Stop the virtual machine;

Update the value of the second bitmap information of each page according to the value of the first bitmap information of each page in the virtual machine, the first bitmap information is used to identify whether each page has been modified, and the second bitmap information The map information is used to identify whether the pages need to be saved, and the first bitmap information and the second bitmap information of the pages are in one-to-one correspondence with the addresses of the pages;

Initialize the value of the first bitmap information of each page in the virtual machine;

resume operation of the virtual machine;

sequentially determine whether the value of the second bitmap information of each page in the virtual machine is the first preset value;

saving each page whose value of the second bitmap information is the first preset value into the buffer area, and changing the value of the second bitmap information of each page saved into the buffer area to the second preset value.

The present invention provides a virtual machine continuous snapshot device, including:

A shutdown module, configured to shut down the virtual machine;

An update module, configured to update the value of the second bitmap information of each page according to the value of the first bitmap information of each page in the virtual machine, the first bitmap information is used to identify whether each page has been modified, The second bitmap information is used to identify whether each page needs to be saved, and the first bitmap information and the second bitmap information of each page are in one-to-one correspondence with the address of each page;

an initialization module, configured to initialize the value of the first bitmap information of each page in the virtual machine;

A recovery module, configured to recover the operation of the virtual machine;

A judging module, configured to sequentially judge whether the value of the second bitmap information of each page in the virtual machine is the first preset value;

A processing module, configured to save each page whose value of the second bitmap information is the first preset value to the buffer area, and change the value of the second bitmap information of each page saved to the buffer area to the second preset value. set value.

In the virtual machine continuous snapshot method and device provided by the present invention, the virtual machine continuous snapshot device only needs to copy the value of the first bitmap information of each page in the virtual machine to the second bitmap information during the shutdown process of the virtual machine. To restore the operation of the virtual machine, during the operation of the virtual machine, snapshots are sequentially saved for each page that needs to be saved according to the value of the second bitmap information of each page. Since the time required for the operation of the bitmap information for each page is very short, The downtime of the virtual machine during a snapshot is shorter, and only the pages modified since the last snapshot need to be saved during continuous snapshots of the virtual machine, so that all pages are only saved once, and the number of saved pages is small, thus greatly shortening The time for one snapshot of the virtual machine is reduced, and the impact of the continuous snapshot process of the virtual machine on the performance of the virtual machine is reduced.

Description of drawings

FIG. 1 is a schematic flowchart of Embodiment 1 of a continuous snapshot method for a virtual machine provided by the present invention;

FIG. 2 is a schematic flow diagram of Embodiment 2 of a virtual machine continuous snapshot method provided by the present invention;

FIG. 3 is a schematic flow diagram of Embodiment 3 of a virtual machine continuous snapshot method provided by the present invention;

FIG. 4 is a schematic structural diagram of Embodiment 1 of a virtual machine continuous snapshot device provided by the present invention;

FIG. 5 is a schematic structural diagram of Embodiment 2 of a virtual machine continuous snapshot device provided by the present invention.

detailed description

FIG. 1 is a schematic flowchart of Embodiment 1 of a method for continuous snapshot of a virtual machine provided by the present invention. As shown in Figure 1, the method includes:

S10, stop the virtual machine.

S11. Update the value of the second bitmap information of each page according to the value of the first bitmap information of each page in the virtual machine.

Wherein, the first bitmap information is used to identify whether each page has been modified, the second bitmap information is used to identify whether each page needs to be saved, the first bitmap information and the second bitmap information of each page The bitmap information is in one-to-one correspondence with the address of each page.

Specifically, this embodiment of the method is executed by a virtual machine continuous snapshot device. The minimum unit of the virtual machine memory in the present invention is a page, and each page corresponds to a page address. The continuous snapshot method of the virtual machine provided by the present invention takes the memory snapshot of the virtual machine as an example to illustrate. Firstly, a bitmap information table is established for each page in the virtual machine, and the bitmap information table includes the addresses and the first Correspondence between the bitmap information and the second bitmap information. The two states of the first bitmap information and the second bitmap information can be represented by a value of one bit respectively. For example, 1 or 0 are respectively used to represent the two states of the first bitmap information and the second bitmap information.

For convenience of description, in each embodiment of the present invention, the value of the first bitmap information is represented by 0 that the page is write-protected and has not been modified, and 1 is used to represent that the page has been modified; the value of the second bitmap information is represented by 1 The page needs to be saved but has not been saved. Use 0 to indicate that the page has been saved or does not need to be saved as an example for illustration.

In this embodiment, when performing continuous snapshots of a virtual machine, the virtual machine is first shut down, and then the value of the first bitmap information in the bitmap information table is copied to the second bitmap information, so that the continuous snapshot device for the virtual machine can Whether the page is modified to determine whether the page needs to be saved. For example, if the virtual machine includes 3 pages in total, when the virtual machine stops, the values of the first bitmap information of the first page and the third page are both 1, and the value of the first bitmap information of the second page is 0 , it means that the first page and the third page have been modified, and the second page has not been modified. After copying the first bitmap information of each page to the second bitmap information, the second bitmap information of the first page and the third page If the map information is 1, and the second bitmap information of the second page is 0, it means that the first page and the third page need to be saved, but the second page does not need to be saved.

S12. Initialize the value of the first bitmap information of each page in the virtual machine.

Specifically, after copying the first bitmap information of each page in the virtual machine to the second bitmap information, in order to record the modification of each page in the snapshot process, initialize the first bitmap information of each page, that is, The value of the first bitmap information of each page is set to 0. Before the next snapshot starts, the virtual machine continuous snapshot device copies the first bitmap information value of each page to the second bitmap information. The modified pages in , so that only the corresponding modified pages are saved.

S13. Resume running of the virtual machine.

It should be noted that the above S11 and S12 are only some simple data operations, and the required time is very short, so that the virtual machine stops for a very short time.

S14, sequentially determine whether the value of the second bitmap information of each page in the virtual machine is a first preset value.

S15, saving each page whose value of the second bitmap information is the first preset value to the buffer area, and changing the value of the second bitmap information of each page saved to the buffer area to the second preset value .

Specifically, the first preset value in this embodiment is 1. After the virtual machine continuous snapshot device is shut down, it only copies the value of the first bitmap information of each page in the virtual machine to the second bitmap information, and resumes the operation of the virtual machine, and then judges the information of each page in the virtual machine in turn. The identifier of the second bitmap information of the page. If the identifier of the second bitmap information of a page is 0, it means that the page has been saved or does not need to be saved. If it is 1, it means that the page needs to be saved but has not been saved. Each page in the virtual machine whose second bitmap information value is 1 is stored in the cache area. In addition, in order to prevent the continuous snapshot device of the virtual machine from sequentially judging whether the second bitmap information of each page is 1, the If the page has been repeatedly judged and saved multiple times, the continuous snapshot device of the virtual machine saves the page to be saved in the cache area according to the second bitmap information identifier, and then the second bitmap information corresponding to the page address ID changed to 0.

In the virtual machine continuous snapshot method provided by the present invention, before the first snapshot of the virtual machine, the value of the second bitmap information of each page in the virtual machine can be uniformly set to 1, so that the virtual machine continuous snapshot device When the machine takes its first snapshot, each page can be saved in the cache in turn. In the subsequent snapshot process, the value of the second bitmap information of each page can be determined according to the value of the first bitmap information of the page. If the page is modified, the value of the second bitmap information of the page is modified to 1, so that the virtual machine continuous snapshot device saves the page in the next snapshot, so that the virtual machine continuous snapshot device only caches the pages that need to be saved each time, ensuring the integrity of the virtual machine continuous snapshot.

In the virtual machine continuous snapshot method provided by the present invention, the virtual machine continuous snapshot device only needs to copy the value of the first bitmap information of each page in the virtual machine to the second bitmap information to restore the virtual machine During the operation of the virtual machine, according to the value of the second bitmap information of each page, the snapshots of each page to be saved are sequentially saved. Since the time required for the operation of the bitmap information of each page is very short, one time During the snapshot process, the downtime of the virtual machine is short, and only the pages modified since the last snapshot need to be saved during the continuous snapshot process of the virtual machine, so that all pages are only saved once, and the number of saved pages is small, which greatly shortens the The time for one snapshot of the virtual machine reduces the impact of the continuous snapshot process of the virtual machine on the performance of the virtual machine. FIG. 2 is a schematic flow chart of Embodiment 2 of the continuous snapshot method of a virtual machine provided by the present invention. As shown in Figure 2, before the above S13, the method also includes:

S20. Write-protect the memory page of the virtual machine.

Specifically, in order to capture the write request to the memory page of the virtual machine in real time, the continuous snapshot device for the virtual machine needs to implement write protection for the virtual machine.

After the above S13, the method also includes:

S21. Intercept a write request for a write-protected memory page of the virtual machine, where the write request includes data to be written and an address of the page to which the data is to be written.

Specifically, when any entity in the network needs to write new data to a page in the virtual machine memory, it can send a write request to the virtual machine. Since the virtual machine is write-protected, the write operation to the memory page will cause the virtual machine to crash. output to the virtual machine monitor, so that the virtual snapshot device can intercept the write request to the virtual machine. Wherein, the write request includes the address of the page where new data is to be written.

S22. Change the value of the first bitmap information related to the page to be written into a third preset value.

Specifically, when the virtual machine continuous snapshot device intercepts a write request, it can determine that the value of the first bitmap information corresponding to the page address in the write request is 0, which means that the page is write-protected and cannot be modified. , the virtual machine continuous snapshot apparatus may change the value of the first bitmap information of the page to 1 to mark the page as modified.

S23, judging whether the value of the second bitmap information of the page to be written with data is a first preset value, if so, execute S24, otherwise execute S25.

S24. Save the page of the data to be written into the cache area.

S25. Remove the write protection of the page of data to be written, and write the data to be written into the page of data to be written.

It should be noted that there is no fixed sequence between the above-mentioned step S20 in this embodiment to write-protect the virtual machine and the above-mentioned S11 and S12, as long as S11, S12 and S20 are executed before S13, as shown in FIG. 2 Take S20 after S12 as an example for illustration. In addition, steps S21-S25 in this embodiment are triggered after the write request to the virtual machine is intercepted, and their execution may be performed simultaneously with the above-mentioned S14 action initiated by the virtual machine continuous snapshot device. The above S14 can be repeatedly executed by the continuous snapshot device of the virtual machine in the background, while the steps S10-S13, S21-S25 need to be implemented in the foreground operation control, that is, the two processes are two threads running in parallel and do not affect each other.

In order to prevent the page of data to be written from being not saved before being modified, in this embodiment, before the page of data to be written is modified, it is first judged whether the page has been stored in the cache area, that is, the second bit of the page is first judged Whether the value of the map information is 1, if it is 1, store the page in the cache area first and then modify the page, if it is 0, it means that the data of the page may have been executed in the virtual machine continuous snapshot device before the above S14 It is stored in the cache area during the process, and there is no need to save it again.

In the virtual machine continuous snapshot method provided by the present invention, the virtual machine continuous snapshot device only needs to copy the value of the first bitmap information of each page in the virtual machine to the second bitmap information to restore the virtual machine When the virtual machine is running, according to the value of the second bitmap information of each page, the snapshots of the pages that need to be saved are saved sequentially. Since the time required for the operation of the bitmap information of each page is very short, it shortens the time required for the virtual machine. The downtime of the virtual machine is reduced, and only the modified pages after the last snapshot need to be saved during the continuous snapshot of the virtual machine, so that all pages are saved only once, and the number of saved pages is small, which greatly shortens the time for a snapshot of the virtual machine , reducing the impact of the continuous snapshot process of the virtual machine on the performance of the virtual machine. In addition, when receiving a write request to the virtual machine, after modifying the value of the first bitmap information of the page to be written to data, first confirm that the page to be written to data has been saved before modifying the page, The state of the page to be written to before and after the data is written can be saved in the two snapshots before and after, which ensures the integrity and continuity of the continuous snapshots of the virtual machine.

FIG. 3 is a schematic flowchart of Embodiment 3 of the continuous snapshot method for a virtual machine provided by the present invention. As shown in Figure 3, the method also includes:

S30, monitor whether the remaining capacity of the buffer area has reached a fourth preset value, if so, execute S31, otherwise execute S34.

Specifically, when the virtual machine continuous snapshot device stores pages into the cache area, it also monitors the remaining capacity of the cache area at the same time, so as to prevent that the cache area is full or the capacity is not enough, and the new pages stored are not saved. . The fifth preset value can be set according to the capacity of the buffer area, such as 1%, 3% or 0 of the capacity of the buffer area. This embodiment does not limit this.

S31. Move the pages stored in the cache area to a designated location, and record the time T1 used.

Since the data in the cache area is transferred to the disk, a large amount of input and output (IO) rate of the host machine will be occupied, thereby affecting the virtual machine's access to IO resources and affecting the performance of the virtual machine, so the embodiment of the present invention You can control the rate at which the virtual machine continuous snapshot device moves the data in the cache area to the specified location.

S32, judging whether the time T1 is less than the preset time T2, if yes, execute S33, otherwise execute S34.

In the embodiment of the present invention, the start time of two consecutive shifts of the data in the cache area to the specified location is regarded as a cycle. If the data in the buffer area can be controlled to be moved to the specified location in each cycle, the IO of the host machine will be occupied. The speed should not affect the IO rate occupied by the virtual machine as far as possible, so as to improve the performance of the virtual machine.

Then the method also includes:

Record the time interval T4 of the virtual machine from the end of the previous operation of moving the pages stored in the cache to the specified location to the current operation of moving the pages stored in the cache to the specified location Actual input and output rate V _vm .

Specifically, during the running of the virtual machine, the data size of each IO operation is recorded. Usually, the IO operation of the virtual machine is in units of sectors, and each sector defaults to 512 bytes, so only each IO operation is recorded when recording The number of sectors to operate is sufficient. Assuming that the total number of recorded sectors in T4 is N, the actual input and output rate V _vm of the virtual machine within T4 can be determined = (N*512)/T4.

According to the maximum input and output rate V _max of the virtual machine and the actual input and output rate V _vm , determine the available input and output rate of the virtual machine V _ava =V _max −V _vm .

Usually, the administrator will give the virtual machine a maximum IO rate V _max when the virtual machine is started, so that the available IO rate V ava of the virtual machine can be determined V _ava =V _max -V _vm .

The preset time T2=S _buf /V _ava is determined according to the current storage capacity S _buf of the buffer area and the available input and output rate V _ava of the virtual machine. If the storage capacity of the buffer area this time is S _buf , the available time for moving the data in the buffer area to the designated location can be determined this time, that is, the preset time T2=S _buf /V _ava =S _buf /(V _max -V _vm )=S _buf /(V _max -(N*512)/T4).

S33, suspending the operation of saving each page whose value of the second bitmap information is the first preset value to the cache area for T3 time, where T3=T2-T1.

If it is determined by comparison that the time T1 used to write the data in the cache area to the disk this time is shorter than the available time T2 in this period, it means that the rate at which the data in the cache area is written to the disk this time may be greater than the available IO rate. To make the rate of writing the data in the cache area to the disk relatively uniform in this cycle, you can suspend the snapshot process of the virtual machine for T3 time, so as to ensure the operation time for writing the data in the cache area to the disk as a whole T1 is equivalent to T2, and then ensures that the speed of writing the data in the cache area to the disk is lower than the above-mentioned available IO rate.

It should be noted that there is no fixed sequence between the above-mentioned processes of S30-S33 and the above-mentioned processes of S10-S14 and S20-S25, they can be parallel processes, or each time the virtual machine continuous snapshot device completes a snapshot, That is to trigger the execution of S30-S33 once, or a fixed time interval can also be set. After each time interval, the virtual machine continuous snapshot device triggers the execution of S30-S33 once, etc., which is not limited in this embodiment .

S34, performing an operation of sequentially judging whether the value of the second bitmap information of each page in the virtual machine is a first preset value.

Specifically, if the virtual machine continuous snapshot device judges that the capacity of the cache area can still save pages, it can continue to judge whether the second bitmap information of each page in the virtual machine is 1, and set the second bitmap information to 1 The pages are stored in the cache.

In the virtual machine continuous snapshot method provided in this embodiment, the virtual machine continuous snapshot device detects the capacity of the cache area at the same time during the process of storing the pages in the virtual machine memory into the cache area, and then timely shifts the pages in the cache area To the specified location, and according to the time to move the pages in the cache area to the specified location, control the time to suspend the snapshot process. By controlling the rate at which the pages in the cache area are moved to the specified location each time, minimize the The impact of moving the pages in the cache area to the specified location on the performance of the virtual machine.

FIG. 4 is a schematic structural diagram of Embodiment 1 of a virtual machine continuous snapshot device provided by the present invention. As shown in FIG. 1 , the virtual machine continuous snapshot device 400 includes: a shutdown module 401 , an update module 402 , an initialization module 403 , a recovery module 404 , a judging module 405 and a processing module 406 . Wherein, the shutdown module 401 is used to stop the virtual machine; the update module 402 is used to update the value of the second bitmap information of each page according to the value of the first bitmap information of each page in the virtual machine, the first bit The map information is used to identify whether each page has been modified, the second bitmap information is used to identify whether each page needs to be saved, the first bitmap information and the second bitmap information of each page are consistent with the One-to-one address correspondence; the initialization module 403 is used to initialize the value of the first bitmap information of each page in the virtual machine; the recovery module 404 is used to restore the operation of the virtual machine; the judging module 405 is used to judge the virtual Whether the value of the second bitmap information of each page in the machine is the first preset value; the processing module 406 is used to save each page whose value of the second bitmap information is the first preset value to the cache area, and The value of the second bitmap information of each page saved in the cache area is changed to a second preset value.

For the specific functions of each module in the virtual machine continuous snapshot device provided in this embodiment and the virtual machine continuous snapshot processing flow, refer to the detailed description of the first embodiment of the virtual machine continuous snapshot method, and will not be repeated here.

In the virtual machine continuous snapshot device provided in this embodiment, the virtual machine continuous snapshot device only needs to copy the value of the first bitmap information of each page in the virtual machine to the second bitmap information during the shutdown process of the virtual machine to recover During the operation of the virtual machine, the snapshots of the pages to be saved are sequentially saved according to the value of the second bitmap information of each page during the running of the virtual machine. Since the time required for the operation of the bitmap information of each page is very short, the The downtime of the virtual machine during a snapshot is short, and only the pages modified since the last snapshot need to be saved during the continuous snapshot of the virtual machine, so that all pages are saved only once, and the number of saved pages is small, thus greatly shortening the The time for one snapshot of the virtual machine is reduced, and the impact of the continuous snapshot process of the virtual machine on the performance of the virtual machine is reduced.

FIG. 5 is a schematic structural diagram of Embodiment 2 of a virtual machine continuous snapshot device provided by the present invention. As shown in FIG. 5 , on the basis of that shown in FIG. 4 , the virtual machine continuous snapshot device 400 further includes: a write protection module 501 and an interception module 502 .

Wherein, the write protection module 501 is used to write-protect the memory page of the virtual machine; the interception module 502 is used to intercept the write request to the write-protected memory page of the virtual machine, and the write request includes the data and the address of the page to be written into the data; the processing module 406 is also used to change the value of the first bitmap information related to the page of the data to be written into a third preset value; the judging module 405 is also used to determine whether the value of the second bitmap information of the page to be written in data is the first preset value; the processing module 406 is also used to write the page of data to be written into Save to the cache area; the processing module 406 is further configured to remove the write protection of the page of the data to be written, and write the data to be written into the page of the data to be written.

Further, the device for continuous snapshot of the virtual machine further includes: a monitoring module 503 .

Wherein, the monitoring module 503 is used to monitor whether the remaining capacity of the cache area has reached the fifth preset value; the processing module 406 is also used to move the pages saved in the cache area to the specified location, and record the time T1 used; the judging module 405 is also used to judge whether the time T1 is less than the preset time T2; the processing module 406 is also used to convert the second bitmap information to The operation of saving each page with the first preset value to the cache area is suspended for T3 time, where T3=T2-T1.

In a possible implementation form of the present invention, the above-mentioned processing module 406 is further configured to, if not, proceed to sequentially determine whether the value of the second bitmap information of each page in the virtual machine is the first preset value operate.

In a preferred implementation form of the present invention, the virtual machine continuous snapshot device 400 further includes: a computing module 504 .

Wherein, the operation module 504 is used to record the time interval from the previous operation of moving the pages stored in the cache to the specified location to the current operation of moving the pages stored in the cache to the specified location The actual input and output rate V _vm of the virtual machine in T4; the operation module 504 is further configured to determine the virtual machine's input and output rate V vm according to the maximum input and output rate V _max of the virtual machine and the actual input and output rate V _vm . available input and output rate V _ava =V _{max -V vm} ; the operation module 504 is also used _to determine the preset Time T2 = S _buf /V _ava .

For the specific functions and processing flow of each module in the virtual machine continuous snapshot device provided in this embodiment, reference may be made to the detailed descriptions of Embodiments 2 and 3 of the above-mentioned virtual machine continuous snapshot processing method, and details are not repeated here.

In the virtual machine continuous snapshot method provided by the present invention, the virtual machine continuous snapshot device only needs to copy the value of the first bitmap information of each page in the virtual machine to the second bitmap information during the shutdown process of the virtual machine, that is, restore the virtual machine When the virtual machine is running, according to the value of the second bitmap information of each page, the snapshots of the pages that need to be saved are sequentially saved. Since the time required for the operation of the bitmap information of each page is very short, the virtual machine is shortened. The downtime of the virtual machine is reduced, and only the modified pages after the last snapshot need to be saved during the continuous snapshot of the virtual machine, so that all pages are saved only once, and the number of saved pages is small, which greatly shortens the time for a snapshot of the virtual machine , reducing the impact of the continuous snapshot process of the virtual machine on the performance of the virtual machine. In addition, when receiving a write request to the virtual machine, after modifying the value of the first bitmap information of the page to be written to data, first confirm that the page to be written to data has been saved before modifying the page, The state of the page to be written to before and after the data is written can be saved in the two snapshots before and after, which ensures the integrity and continuity of the continuous snapshots of the virtual machine. In addition, according to the time when the pages in the cache area are moved to the specified location, the time to suspend the snapshot process is controlled. Impact on virtual machine performance during snapshot migration.

Those of ordinary skill in the art can understand that all or part of the steps for implementing the above method embodiments can be completed by program instructions and related hardware. The aforementioned program can be stored in a computer-readable storage medium. When the program is executed, it executes the steps of the above-mentioned method embodiments; and the aforementioned storage medium includes: ROM, RAM, magnetic disk or optical disk and other various media that can store program codes.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than limiting them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: It is still possible to modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the technical solutions of the various embodiments of the present invention. scope.

Claims (10)

1. A virtual machine continuous snapshot method, characterized in that, comprising: shut down the virtual machine; Update the value of the second bitmap information of each page according to the value of the first bitmap information of each page in the virtual machine, the first bitmap information is used to identify whether each page has been modified, and the second bitmap information The map information is used to identify whether the pages need to be saved, and the first bitmap information and the second bitmap information of the pages are in one-to-one correspondence with the addresses of the pages; Initialize the value of the first bitmap information of each page in the virtual machine; resume operation of the virtual machine; sequentially determine whether the value of the second bitmap information of each page in the virtual machine is the first preset value; saving each page whose value of the second bitmap information is the first preset value into the buffer area, and changing the value of the second bitmap information of each page saved into the buffer area to the second preset value. 2. The virtual machine continuous snapshot method according to claim 1, wherein, before restoring the operation of the virtual machine, further comprising: Write-protecting the memory page of the virtual machine; Before and after the restoration of the operation of the virtual machine, it also includes: Intercepting a write request to the write-protected memory page of the virtual machine, where the write request includes the data to be written and the address of the page to which the data is to be written; changing the value of the first bitmap information of the page to be written into a third preset value; judging whether the value of the second bitmap information of the page to be written with data is a first preset value; If so, then save the page of the data to be written into the cache area; removing the write protection of the page of the data to be written, and writing the data to be written into the page of the data to be written. 3. The virtual machine continuous snapshot method according to claim 1 or 2, further comprising: monitoring whether the remaining capacity of the buffer area has reached a fourth preset value; If so, then move the pages stored in the cache to a designated location, and record the time T1 used; judging whether the time T1 is less than a preset time T2; If so, suspend the operation of saving each page whose value of the second bitmap information is the first preset value to the cache area for T3 time, where T3=T2-T1. 4. The virtual machine continuous snapshot method according to claim 3, wherein after the judging whether the time T1 is less than the preset time T2, further comprising: If not, continue to execute the operation of sequentially judging whether the value of the second bitmap information of each page in the virtual machine is the first preset value. 5. The virtual machine continuous snapshot method according to claim 4, further comprising: Record the time interval T4 of the virtual machine from the end of the previous operation of moving the pages stored in the cache to the specified location to the current operation of moving the pages stored in the cache to the specified location Actual input and output rate V _vm ; According to the maximum input and output rate V _max of the virtual machine and the actual input and output rate V _vm , determine the available input and output rate of the virtual machine V _ava = V _max - V _vm ; The preset time T2=S _buf /V _ava is determined according to the current storage capacity S _buf of the buffer area and the available input and output rate V _ava of the virtual machine. 6. A virtual machine continuous snapshot device, comprising: A shutdown module, configured to shut down the virtual machine; An update module, configured to update the value of the second bitmap information of each page according to the value of the first bitmap information of each page in the virtual machine, the first bitmap information is used to identify whether each page has been modified, The second bitmap information is used to identify whether each page needs to be saved, and the first bitmap information and the second bitmap information of each page are in one-to-one correspondence with the address of each page; an initialization module, configured to initialize the value of the first bitmap information of each page in the virtual machine; A recovery module, configured to recover the operation of the virtual machine; A judging module, configured to sequentially judge whether the value of the second bitmap information of each page in the virtual machine is the first preset value; A processing module, configured to save each page whose value of the second bitmap information is the first preset value to the buffer area, and change the value of the second bitmap information of each page saved to the buffer area to the second preset value. set value. 7. The virtual machine continuous snapshot device according to claim 6, further comprising: A write protection module, configured to write protect the memory pages of the virtual machine; An intercepting module, configured to intercept a write request to the write-protected memory page of the virtual machine, where the write request includes the data to be written and the address of the page to be written; The processing module is further configured to change the value of the first bitmap information of the page to be written into a third preset value; The judging module is also used to judge whether the value of the second bitmap information of the page to be written is the first preset value; The processing module is further configured to save the page of the data to be written into the cache area if so; The processing module is further configured to remove the write protection of the page of data to be written, and write the data to be written into the page of data to be written. 8. The virtual machine continuous snapshot device according to claim 6 or 7, further comprising: A monitoring module, configured to monitor whether the remaining capacity of the buffer area has reached a fifth preset value; The processing module is further configured to, if yes, move the pages stored in the cache to a specified location, and record the time T1 used; The judging module is also used to judge whether the time T1 is less than a preset time T2; The processing module is further configured to suspend the operation of saving each page whose value of the second bitmap information is the first preset value to the cache area for T3 time if yes, the T3=T2-T1 . 9. The virtual machine continuous snapshot device according to claim 8, wherein: The processing module is further configured to, if not, continue to execute the operation of sequentially judging whether the value of the second bitmap information of each page in the virtual machine is the first preset value. 10. The virtual machine continuous snapshot device according to claim 9, further comprising: The operation module is used to record the time interval T4 from the end of the previous operation of moving the pages stored in the cache to the specified location to the current operation of moving the pages stored in the cache to the specified location The actual input and output rate V _vm of the virtual machine; The computing module is further configured to determine the available input and output rate of the virtual machine V _ava =V _max -V _vm according to the maximum input and output rate V _max of the virtual machine and the actual input and output rate V _vm ; The calculation module is further configured to determine the preset time T2=S _buf /V _ava according to the current storage capacity S _buf of the buffer area and the available input and output rate V _ava of the virtual machine.