WO2020237849A1

WO2020237849A1 - Snapshot read-write method for network block device, apparatus, device, and storage medium

Info

Publication number: WO2020237849A1
Application number: PCT/CN2019/101713
Authority: WO
Inventors: 王新
Original assignee: 平安科技（深圳）有限公司
Priority date: 2019-05-31
Filing date: 2019-08-21
Publication date: 2020-12-03
Also published as: CN110321321B; CN110321321A

Abstract

The present application discloses a snapshot read-write method for a network block device, an apparatus, a device, and a storage medium. The method comprises: when a Ceph client detects that a snapshot database of a network block device has received a snapshot read-write request, sending, on the basis of an rbd-nbd process corresponding to the network block device, the snapshot read-write request to a Ceph cluster so as to acquire snapshot data fed back by the Ceph cluster in response to the snapshot read-write request; acquiring the snapshot read-write request type; if the snapshot read-write request type is write, performing a write operation in the rbd-nbd process according to the write type, so as to acquire written data; and feeding the written data and the snapshot data back to the network block device so as to start the snapshot database in the network block device. The present application aims to resolve the technical issue of the prior art by means of a distributed system, and in which creating a writable snapshot file system or a writable snapshot database system of an nbd device is difficult.

Description

Method, device, device and storage medium for reading and writing snapshots of network block equipment To

This application claims the priority of a Chinese patent application filed with the Chinese Patent Office on May 31, 2019, the application number is 201910480680.4, and the invention title is "Network block device snapshot reading and writing methods, devices, equipment, and storage media". The entire content Incorporated in the application by reference.

Technical field

This application relates to the field of computer technology, and in particular to a method, device, device, and storage medium for reading and writing snapshots of network block devices.

Background technique

Ceph distributed system includes Ceph clients and Ceph clusters. Among them, Ceph clients include network block devices (network block device), the network block device is referred to as nbd device, and the nbd device is a block device widely used by the Linux system of the Ceph client. Among them, the Ceph client can select a created nbd device locally, and use the preset nbd The protocol connects the rbd device of the Ceph cluster. Specifically, the rbd device can be understood as a storage device in the Ceph cluster. It should be noted that in the Ceph distributed system, the read and write on the Ceph client nbd device needs to be converted to Ceph The read and write of the rbd device in the cluster, after the read and write of the rbd device in the Ceph cluster is completed, the read and write content of the rbd device is obtained and returned to the Ceph client nbd device to complete the read and write to the Ceph client nbd device.

In the Ceph distributed system, if you connect the snapshot storage volume imageA in the rbd device through the nbd device to create a snapshot file system on the nbd device, or deploy a snapshot database system, the snapshot file system or the snapshot database system is in the Ceph cluster It is a read-only attribute, and it is difficult to meet the needs of creating a writable snapshot file system for nbd devices or a writable snapshot database system.

Summary of the invention

The main purpose of this application is to provide a method, device, device, and storage medium for reading and writing snapshots of network block devices, which aims to solve the problem of creating a writable snapshot file system of nbd devices or a writable snapshot database system in the prior art. Technical issues.

In order to achieve the above purpose, this application provides a network block device snapshot read and write method. The network block device snapshot read and write method is applied to a Ceph client in a Ceph distributed system. The Ceph distributed system also includes a Ceph cluster. The network block device snapshot read-write method includes:

When the Ceph client detects a read and write snapshot request for the snapshot database of the network block device, it sends the read and write snapshot request to the Ceph cluster based on the rbd-nbd process corresponding to the network block device to obtain all The snapshot data fed back by the Ceph cluster in response to the read-write snapshot request;

Acquiring the type of the read-write snapshot request;

If the type of the read-write snapshot request is a write request type, perform a write operation in the rbd-nbd process according to the write type to obtain write data;

The write data and the snapshot data are fed back to the network block device to start the snapshot database in the network block device.

Optionally, if the type of the read-write snapshot request is a write type, performing a write operation in the rbd-nbd process according to the write type to obtain write data includes:

If the type of the read-write snapshot request is the type of the write request, determining whether the cache in the rbd-nbd process is empty;

If the cache in the rbd-nbd process is not empty, acquire the first key value carried in the write request, where the first key value includes write position and write length information;

Comparing the first key value with the second key value in the cached entry in the cache;

If the first key value is less than or equal to the second key value, a new cache entry is added to the cache, and the requested content of the write request is stored in the new cache entry.

Optionally, after the step of judging whether the cache in the rbd-nbd process is empty includes:

If the cache in the rbd-nbd process is empty, an initial entry will be created in the cache;

The request content of the write request is stored in the initial entry in the rbd-nbd process.

Optionally, after the step of comparing the first key value with the second key value in the cached entry in the cache includes:

If the first key value is greater than the second key value, the request content of the write request corresponding to the first key value and the request content corresponding to the second key are merged and stored.

Optionally, after the step of obtaining the type of the read-write snapshot request, the method includes:

If the type of the read-write snapshot request is a read type, the snapshot data fed back by the Ceph cluster in response to the read-write snapshot request is fed back to the network block device to start the snapshot database in the network block device.

Optionally, if the type of the read-write snapshot request is a read type, the step of feeding back the snapshot data fed back by the Ceph cluster for the read-write snapshot request to the network block device includes:

If the type of the read-write snapshot request is a read type, determining whether the cache in the rbd-nbd process is empty;

If the cache in the rbd-nbd process is not empty, obtain the target read key value carried in the read request, and obtain the read data of the read request from the cache according to the target read key value;

The snapshot data and the read data fed back by the Ceph cluster for the read-write snapshot request are fed back to the network block device.

This application also provides a network block device snapshot reading and writing device, the network block device snapshot reading and writing device is applied to a Ceph client in a Ceph distributed system, the Ceph distributed system also includes a Ceph cluster, and the network block The device snapshot reading and writing device includes:

The detection module is used to send the read and write snapshot request to the Ceph based on the rbd-nbd process corresponding to the network block device when the Ceph client detects a read and write snapshot request to the snapshot database of the network block device Cluster to obtain the snapshot data fed back by the Ceph cluster in response to the read-write snapshot request;

An obtaining module, used to obtain the type of the read-write snapshot request;

A write module, configured to perform a write operation in the rbd-nbd process according to the write type when the type of the read-write snapshot request is a write request type to obtain write data;

The feedback module is used to feed back the write data and the snapshot data to the network block device to start the snapshot database in the network block device.

Optionally, the writing module includes:

The first determining unit is configured to determine whether the cache in the rbd-nbd process is empty if the type of the read-write snapshot request is the type of the write request;

The first obtaining unit is configured to obtain a first key value carried in the write request if the cache in the rbd-nbd process is not empty, wherein the first key value includes a write position and a write length information;

A comparison unit, configured to compare the first key value with the second key value in the cached entry in the cache;

The adding unit is configured to add a new cache entry in the cache if the first key value is less than or equal to the second key value, and store the requested content of the write request in the new cache entry.

Optionally, the writing module includes:

A creation unit, configured to create an initial entry in the cache if the cache in the rbd-nbd process is empty;

The first storage unit is configured to store the request content of the write request in the initial entry in the rbd-nbd process.

Optionally, the writing module further includes:

The second storage unit is configured to merge and merge the request content of the write request corresponding to the first key value and the request content corresponding to the second key if the first key value is greater than the second key value storage.

Optionally, the apparatus for reading and writing a snapshot of a network block device further includes:

The startup module is used to feed back the snapshot data fed back by the Ceph cluster in response to the read-write snapshot request to the network block device if the type of the read-write snapshot request is a read type, so as to start the network block device Snapshot database in.

Optionally, the startup module includes:

The second determining unit is configured to determine whether the cache in the rbd-nbd process is empty if the type of the read-write snapshot request is a read type;

The second obtaining unit is configured to obtain the target read key value carried in the read request if the cache in the rbd-nbd process is not empty, and obtain the target read key value from the cache according to the target read key value. Read data of the read request;

The feedback unit is configured to feed back the snapshot data and the read data fed back by the Ceph cluster for the read-write snapshot request to the network block device.

In addition, in order to achieve the above object, this application also provides a network block device snapshot read-write device, the network block device snapshot read-write device includes: a memory, a processor, a communication bus, and a network block device stored on the memory Readable instructions for snapshot read and write methods,

The communication bus is used to realize the communication connection between the processor and the memory;

The processor is configured to execute the readable instructions of the network block device snapshot read and write method to implement the following steps:

Acquiring the type of the read-write snapshot request;

In addition, in order to achieve the above object, the present application also provides a storage medium that stores one or more readable instructions, and the one or more readable instructions can be executed by one or more processors to Used for:

Acquiring the type of the read-write snapshot request;

This application sends the read and write snapshot request to the Ceph cluster based on the rbd-nbd process corresponding to the network block device when the Ceph client detects the read and write snapshot request to the snapshot database of the network block device, To obtain the snapshot data fed back by the Ceph cluster in response to the read-write snapshot request; obtain the type of the read-write snapshot request; if the type of the read-write snapshot request is a write request type, the type of A write operation is performed in the rbd-nbd process to obtain write data; the write data and the snapshot data are fed back to the network block device to start the snapshot database in the network block device. In this application, when a read-write snapshot request of a network block device is detected, the corresponding snapshot data is obtained from the Ceph cluster, and then the type of the read-write snapshot request is obtained. If the type of the read-write snapshot request is the write type, the write The write content in the request is designed to be carried out and cached in the rbd-nbd process, so that the nbd device can detect the snapshot data and the write data corresponding to the write request, so that the nbd device can be processed based on the snapshot data and the write data corresponding to the write request. The creation of a writable snapshot file system, or a writable snapshot database system, thus solves the technical problem of creating a writable snapshot file system of an nbd device or a writable snapshot database system in the prior art.

Description of the drawings

1 is a schematic flowchart of a first embodiment of a method for reading and writing a snapshot of a network block device according to the application;

2 is a schematic flowchart of a second embodiment of a method for reading and writing a snapshot of a network block device according to the application;

FIG. 3 is a schematic diagram of the device structure of the hardware operating environment involved in the method of the embodiment of the present application.

The realization of the purpose, functional characteristics and advantages of the application will be further described in conjunction with the embodiments and with reference to the accompanying drawings.

Detailed ways

It should be understood that the specific embodiments described here are only used to explain the application, and are not used to limit the application.

This application provides a method for reading and writing a snapshot of a network block device. In the first embodiment of the method for reading and writing a snapshot of a network block device according to this application, referring to FIG. 1, the method for reading and writing a snapshot of the network block device is applied to a Ceph distributed system The Ceph distributed system also includes a Ceph cluster, and the network block device snapshot read-write method includes:

Step S10, when the Ceph client detects a read and write snapshot request to the snapshot database of the network block device, it sends the read and write snapshot request to the Ceph cluster based on the rbd-nbd process corresponding to the network block device, To obtain the snapshot data fed back by the Ceph cluster in response to the read-write snapshot request;

Step S20, acquiring the type of the read-write snapshot request;

Step S30, if the type of the read-write snapshot request is a write request type, perform a write operation in the rbd-nbd process according to the write type to obtain write data;

Step S40, feeding back the write data and the snapshot data to the network block device to activate the snapshot database in the network block device.

Specific steps are as follows:

It should be noted that, in this embodiment, the Ceph distributed system includes a Ceph client, and the Ceph distributed system also includes a Ceph cluster. In this embodiment, the data content in the Ceph cluster is mapped to the Ceph client. The network driver is mapped to the local, that is, the Ceph client. To achieve the Ceph client mapping the data content in the Ceph cluster to the local (Ceph client) through the mapped network driver, the rbd-nbd process needs to be artificially triggered by the Ceph client first Among them, the two ends of the rbd-nbd process connection are the Ceph client and the Ceph cluster respectively. Triggering the rbd-nbd process manually is to manually select the Ceph cluster and the local disk on the Ceph client by the user. After the selection is completed, the rbd-nbd process is created by clicking and other operations. After the rbd-nbd process is determined to be created, the nbd device is created in the local disk of the Ceph client based on the rbd-nbd process. After the nbd device is created , The user can read or write the data of the Ceph cluster to the local nbd device to complete the reading and writing of the local nbd device. In other words, the read and write on the Ceph client nbd device needs to be converted. In order to read and write to the rbd device in the Ceph cluster, after the read and write of the rbd device in the Ceph cluster is completed, the read and write content of the rbd device is obtained and returned to the Ceph client nbd device to complete the read and write to the Ceph client nbd device .

In order to facilitate understanding, the Ceph cluster can be regarded as a network neighbor device. If you want to read the data content of the network neighbor device locally, you need to first determine the network neighbor device address and local disk by the user. After the device address and the local disk, the rbd-nbd process is then triggered. According to the rbd-nbd process, the nbd device is created in the local disk, and based on the rbd-nbd process, the corresponding content is obtained from the network neighbor, and the corresponding The content is stored in the nbd device to determine the completion of the reading and writing of the nbd device.

After the network block device is created, if the Ceph client detects a read-write snapshot request to the snapshot database of the network block device, the read-write snapshot request is sent based on the rbd-nbd process corresponding to the network block device To the Ceph cluster to obtain the snapshot data fed back by the Ceph cluster for the read-write snapshot request. Specifically, when a read-write snapshot request is detected, the driver corresponding to the network block device will obtain the read-write snapshot request, Then forward the read-write snapshot request to the socket structure in the Ceph client. The socket structure connects the rbd-nbd process and the nbd device. The rbd-nbd process obtains the read-write snapshot request from the socket structure, and then reads and writes The snapshot request is sent to the Ceph cluster. After receiving the read-write snapshot request, the Ceph cluster will return the snapshot data based on the read request in the read-write snapshot request. It should be noted that in this embodiment, one end of the rbd-nbd process It is the snapshot volume of the rbd device of the Ceph cluster, that is, because one end of the rbd-nbd process is the snapshot volume of the rbd device of the Ceph cluster, the technical problem in this application will exist.

After the Ceph cluster receives the read-write snapshot request, it will return the snapshot data based on the read request in the read-write snapshot request. The process includes: Ceph cluster parses the read request content of the read-write snapshot request, and returns the snapshot data according to the read request content It should be noted that the Ceph cluster returns the snapshot data based on the content of the read request, which belongs to the prior art and does not make a specific description.

Step S20, acquiring the type of the read-write snapshot request;

After obtaining the snapshot data, the type of the read-write snapshot request is determined. The purpose of determining the type of the read-write snapshot request is to determine whether a write operation is required.

If the type of read and write snapshot request is read, no write operation is required;

If the type of the read-write snapshot request is a write type, a write operation is required.

It should be noted that if the type of the read-write snapshot request is a write request type, a write operation is required. In this embodiment, the write operation is designed in the rbd-nbd process to complete the read-write snapshot request Write request, that is, in this embodiment, as long as it is determined that the type of the read-write snapshot request is a write request type, a temporary cache is opened in the local rbd-nbd process to perform a write operation to obtain write data.

Specifically, referring to FIG. 2, if the type of the read-write snapshot request is a write type, performing a write operation in the rbd-nbd process according to the write type to obtain write data includes:

Step S31, if the type of the read-write snapshot request is the type of the write request, determine whether the cache in the rbd-nbd process is empty;

In this embodiment, the cache in the rbd-nbd process may have previously written data. For example, after a previous write operation to the nbd device, it is found that there is an error in the content of the write operation, and a new write operation is required. At this time, The previously written data of the erroneous write operation exists in the rbd-nbd process, and it is necessary to determine whether the cache in the rbd-nbd process is empty when the re-write operation is correspondingly performed.

Step S32, if the cache in the rbd-nbd process is not empty, obtain a first key value carried in the write request, where the first key value includes write position and write length information;

If the cache in the rbd-nbd process is not empty, there is corresponding prior write data. At this time, the first key value and the write content carried in the write request are acquired, where the first key value It includes writing position and writing length information, and the writing content also includes data to be written. The first key value includes writing position and writing length information, that is, KEY=offset+len.

Step S33, comparing the first key value with the second key value in the cached entry in the cache;

After the first key value is obtained, the first key value is compared with the second key value in the cached entry in the cache, and the write position in the first key value is compared with the second key value. The writing position in the key value is compared. If the writing position in the first key value is different from the writing position or the writing length in the second key value, then no subsequent writing content comparison is performed. If the first key value is compared The write position in is the same as the write position or the write length in the second key value, then the write content in the write request is compared with the write content in the corresponding second key value.

Step S34: If the first key value is less than or equal to the second key value, a new cache entry is added to the cache, and the requested content of the write request is stored in the new cache entry.

If the write position in the first key value is different from the write position or write length in the second key value, the first key value is less than or equal to the second key value, and if the first key value is less than or equal to the second key value Key value, a new cache entry is added to the cache, and the requested content of the write request is stored in the new cache entry.

After the step of judging whether the cache in the rbd-nbd process is empty includes:

Step S35, if the cache in the rbd-nbd process is empty, an initial entry will be created in the cache;

Step S36: Store the request content of the write request in the initial entry in the rbd-nbd process.

In this embodiment, if the cache in the rbd-nbd process is empty, an initial entry will be created in the cache, and the request content of the write request will be stored in the initial entry in the rbd-nbd process, In order to complete the write operation locally to obtain the write data.

After obtaining the write data and the snapshot data, the write data and the snapshot data are fed back to the network block device, the network block device detects the write data and the snapshot data corresponding to the write request, and performs the The snapshot data in the network block device is started, that is, when the write data corresponding to the write request is detected in the nbd device, the snapshot database can be started.

Further, the present application provides another embodiment of a method for reading and writing a snapshot of a network block device. In this embodiment, the first key value is compared with the second key value in the cached entry in the cache. After the steps include:

Step S37: If the first key value is greater than the second key value, the request content of the write request corresponding to the first key value and the request content corresponding to the second key are combined and stored.

In this embodiment, if the first key value is greater than the second key value, the request content of the write request corresponding to the first key value and the request content corresponding to the second key are combined and stored. Merged storage refers to writing and storing different parts of the writing content corresponding to the first key value and the writing content corresponding to the second key value, and removing the wrong content in the writing content corresponding to the second key value. The same part of the writing content corresponding to the key value and the writing content corresponding to the second key value is not processed.

In this embodiment, if the first key value is greater than the second key value, the request content of the write request corresponding to the first key value and the request content corresponding to the second key are combined and stored. Determine the correctness of the write operation.

Further, this application provides another embodiment of a method for reading and writing a snapshot of a network block device. In this embodiment, the step of obtaining the type of the read and write snapshot request includes:

Step A1: If the type of the read-write snapshot request is the read type, the snapshot data fed back by the Ceph cluster for the read-write snapshot request is fed back to the network block device to start the network block device Snapshot the database.

In this embodiment, if the type of the read-write snapshot request is a read type, the snapshot data fed back by the Ceph cluster for the read-write snapshot request is fed back to the network block device to start the network block The snapshot database in the device, that is, for the read request, the snapshot data can be returned directly.

If the type of the read-write snapshot request is a read type, the step of feeding back the snapshot data fed back by the Ceph cluster for the read-write snapshot request to the network block device includes:

Step B1, if the type of the read-write snapshot request is a read type, it is determined whether the cache in the rbd-nbd process is empty;

In this embodiment, if the type of the read-write snapshot request is a read type, it is determined whether the cache in the rbd-nbd process is empty, and the purpose of determining whether the cache in the rbd-nbd process is empty is to: Determine whether the nbd device corresponding to the degree request has corresponding read data in the rbd-nbd process before.

Step B2: If the cache in the rbd-nbd process is not empty, obtain the target read key value carried in the read request, and obtain the read request of the read request from the cache according to the target read key value. data;

If the cache in the rbd-nbd process is not empty, the corresponding read data is obtained. Specifically, the target read key value carried in the read request is obtained from the cache according to the target read key value. Read the requested read data,

Step B3, feeding back the snapshot data and the read data fed back by the Ceph cluster for the read-write snapshot request to the network block device.

After the read data is obtained, the snapshot data fed back by the Ceph cluster for the read-write snapshot request and the read data are fed back to the network block device.

Wherein, if the type of the read-write snapshot request is a read type, after the step of judging whether the cache in the rbd-nbd process is empty, the method further includes:

If the cache in the rbd-nbd process is empty, the snapshot data fed back by the Ceph cluster for the read-write snapshot request can be fed back to the network block device.

In this embodiment, if the type of the read-write snapshot request is the read type, it is determined whether the cache in the rbd-nbd process is empty; if the cache in the rbd-nbd process is not empty, then obtain The target read key value carried in the read request, the read data of the read request is obtained from the cache according to the target read key value; the snapshot data fed back by the Ceph cluster for the read and write snapshot request is compared with The read data is fed back to the network block device, and a read request to nbd is implemented in this embodiment.

Referring to FIG. 3, FIG. 3 is a schematic diagram of the device structure of the hardware operating environment involved in the solution of the embodiment of the present application.

The snapshot reading and writing device of the network block device in the embodiment of this application can be a PC, a smart phone, a tablet computer, an e-book reader, MP3 (Moving Picture Experts Group Audio Layer III, moving picture experts compress standard audio layer 3) player, MP4 (Moving Picture Experts) Group Audio Layer IV, dynamic image experts compress standard audio layer 3) Players, portable computers and other terminal equipment.

As shown in FIG. 3, the network block device snapshot read-write device may include a processor 1001, such as a CPU, a memory 1005, and a communication bus 1002. Among them, the communication bus 1002 is used to implement connection and communication between the processor 1001 and the memory 1005. The memory 1005 can be a high-speed RAM memory or a stable memory (non-volatile memory), such as disk storage. Optionally, the memory 1005 may also be a storage device independent of the foregoing processor 1001.

Optionally, the network block device snapshot read-write device may also include a target user interface, network interface, camera, RF (Radio Frequency (radio frequency) circuits, sensors, audio circuits, WiFi modules, etc. The target user interface may include a display screen (Display) and an input unit such as a keyboard (Keyboard), and the optional target user interface may also include a standard wired interface and a wireless interface. The optional network interface can include standard wired interface and wireless interface (such as WI-FI interface).

Those skilled in the art can understand that the network block device snapshot read-write device structure shown in FIG. 3 does not constitute a limitation on the network block device snapshot read-write device, and may include more or less components than shown in the figure, or a combination Certain components, or different component arrangements.

As shown in FIG. 3, the memory 1005 as a computer storage medium may include an operating system, a network communication module, and readable instructions for a network block device snapshot reading and writing method. The operating system is a readable instruction for managing and controlling the hardware and software resources of the network block device snapshot reading and writing device, and supports the operation of the network block device snapshot reading and writing method readable instructions and other software and/or readable instructions. The network communication module is used to implement communication between various components in the memory 1005, and to communicate with other hardware and software in the network block device snapshot read-write device.

In the network block device snapshot reading and writing device shown in FIG. 3, the processor 1001 is configured to execute the readable instructions of the network block device snapshot reading and writing method stored in the memory 1005 to implement the network block device snapshot reading described above. Write method steps.

The specific implementation of the network block device snapshot read-write device of this application is basically the same as the foregoing embodiments of the network block device snapshot read-write method, and will not be repeated here.

The specific implementation of the network block device snapshot reading and writing apparatus of the present application is basically the same as the foregoing embodiments of the network block device snapshot reading and writing method, and will not be repeated here.

The present application provides a storage medium, the storage medium may be a non-volatile readable storage medium, the storage medium stores one or more readable instructions, the one or more readable instructions may also be One or more processors are executed to implement the steps of the network block device snapshot reading and writing method described above.

The specific implementation of the storage medium of the present application is basically the same as the foregoing embodiments of the network block device snapshot reading and writing method, and will not be repeated here.

The above are only preferred embodiments of this application, and do not limit the scope of this application. Any equivalent structure or equivalent process transformation made using the content of the description and drawings of this application, or directly or indirectly used in other related technical fields , The same reason is included in the scope of patent processing of this application.

Claims

A method for reading and writing a snapshot of a network block device is characterized in that the method for reading and writing a snapshot of a network block device is applied to a Ceph client in a Ceph distributed system. The Ceph distributed system also includes a Ceph cluster. The network block Device snapshot read and write methods include:

When the Ceph client detects a read and write snapshot request for the snapshot database of the network block device, it sends the read and write snapshot request to the Ceph cluster based on the rbd-nbd process corresponding to the network block device to obtain all The snapshot data fed back by the Ceph cluster in response to the read-write snapshot request;

Acquiring the type of the read-write snapshot request;

If the type of the read-write snapshot request is a write request type, perform a write operation in the rbd-nbd process according to the write type to obtain write data;

The write data and the snapshot data are fed back to the network block device to start the snapshot database in the network block device.
The method for reading and writing a snapshot of a network block device according to claim 1, wherein if the type of the read and write snapshot request is a write type, writing is performed in the rbd-nbd process according to the write type. The operation to obtain the write data includes:

If the type of the read-write snapshot request is the type of the write request, determining whether the cache in the rbd-nbd process is empty;

If the cache in the rbd-nbd process is not empty, acquire the first key value carried in the write request, where the first key value includes write position and write length information;

Comparing the first key value with the second key value in the cached entry in the cache;

If the first key value is less than or equal to the second key value, a new cache entry is added to the cache, and the requested content of the write request is stored in the new cache entry.
The method for reading and writing a snapshot of a network block device according to claim 2, wherein after the step of obtaining the type of the read and write snapshot request includes:

If the type of the read-write snapshot request is a read type, the snapshot data fed back by the Ceph cluster in response to the read-write snapshot request is fed back to the network block device to start the snapshot database in the network block device.
The method for reading and writing a snapshot of a network block device according to claim 2, wherein if the type of the read-write snapshot request is a read type, the Ceph cluster responds to the snapshot of the read-write snapshot request The step of feeding back data to the network block device includes:

If the type of the read-write snapshot request is a read type, determining whether the cache in the rbd-nbd process is empty;

If the cache in the rbd-nbd process is not empty, obtain the target read key value carried in the read request, and obtain the read data of the read request from the cache according to the target read key value;

The snapshot data and the read data fed back by the Ceph cluster for the read-write snapshot request are fed back to the network block device.
The method for reading and writing a snapshot of a network block device according to claim 2, wherein after the step of judging whether the cache in the rbd-nbd process is empty comprises:

If the cache in the rbd-nbd process is empty, an initial entry will be created in the cache;

The request content of the write request is stored in the initial entry in the rbd-nbd process.
The method for reading and writing a snapshot of a network block device according to claim 5, wherein after the step of obtaining the type of the read and write snapshot request comprises:

If the type of the read-write snapshot request is a read type, the snapshot data fed back by the Ceph cluster in response to the read-write snapshot request is fed back to the network block device to start the snapshot database in the network block device.
The method for reading and writing a snapshot of a network block device according to claim 5, wherein if the type of the read-write snapshot request is a read type, the Ceph cluster responds to the snapshot of the read-write snapshot request The step of feeding back data to the network block device includes:

If the type of the read-write snapshot request is a read type, determining whether the cache in the rbd-nbd process is empty;

If the cache in the rbd-nbd process is not empty, obtain the target read key value carried in the read request, and obtain the read data of the read request from the cache according to the target read key value;

The snapshot data and the read data fed back by the Ceph cluster for the read-write snapshot request are fed back to the network block device.
The method for reading and writing a snapshot of a network block device according to claim 2, wherein after the step of comparing the first key value with the second key value in the cached entry in the cache, the step comprises:

If the first key value is greater than the second key value, the request content of the write request corresponding to the first key value and the request content corresponding to the second key are combined and stored.
8. The method for reading and writing a snapshot of a network block device according to claim 8, wherein after the step of comparing the first key value with the second key value in the cached entry in the cache, the step comprises:

If the first key value is greater than the second key value, the request content of the write request corresponding to the first key value and the request content corresponding to the second key are combined and stored.
The method for reading and writing a snapshot of a network block device according to claim 8, wherein after the step of obtaining the type of the read and write snapshot request comprises:

If the type of the read-write snapshot request is a read type, the snapshot data fed back by the Ceph cluster in response to the read-write snapshot request is fed back to the network block device to start the snapshot database in the network block device.
The method for reading and writing a snapshot of a network block device according to claim 8, wherein if the type of the read-write snapshot request is a read type, the Ceph cluster responds to the snapshot of the read-write snapshot request The step of feeding back data to the network block device includes:

If the type of the read-write snapshot request is a read type, determining whether the cache in the rbd-nbd process is empty;

If the cache in the rbd-nbd process is not empty, obtain the target read key value carried in the read request, and obtain the read data of the read request from the cache according to the target read key value;

The snapshot data and the read data fed back by the Ceph cluster for the read-write snapshot request are fed back to the network block device.
The method for reading and writing a snapshot of a network block device according to claim 1, wherein after the step of obtaining the type of the read and write snapshot request, the method comprises:

If the type of the read-write snapshot request is a read type, the snapshot data fed back by the Ceph cluster in response to the read-write snapshot request is fed back to the network block device to start the snapshot database in the network block device.
The method for reading and writing a snapshot of a network block device according to claim 12, wherein if the type of the read-write snapshot request is a read type, the Ceph cluster responds to the snapshot of the read-write snapshot request The step of feeding back data to the network block device includes:

If the type of the read-write snapshot request is a read type, determining whether the cache in the rbd-nbd process is empty;

If the cache in the rbd-nbd process is not empty, obtain the target read key value carried in the read request, and obtain the read data of the read request from the cache according to the target read key value;

The snapshot data and the read data fed back by the Ceph cluster for the read-write snapshot request are fed back to the network block device.
The method for reading and writing a snapshot of a network block device according to claim 1, wherein if the type of the read-write snapshot request is a read type, the Ceph cluster responds to the snapshot of the read-write snapshot request The step of feeding back data to the network block device includes:

If the type of the read-write snapshot request is a read type, determining whether the cache in the rbd-nbd process is empty;

If the cache in the rbd-nbd process is not empty, obtain the target read key value carried in the read request, and obtain the read data of the read request from the cache according to the target read key value;

The snapshot data and the read data fed back by the Ceph cluster for the read-write snapshot request are fed back to the network block device.
A network block device snapshot reading and writing device, characterized in that the network block device snapshot reading and writing device is applied to a Ceph client in a Ceph distributed system, the Ceph distributed system also includes a Ceph cluster, and the network block The device snapshot reading and writing device includes:

The detection module is used to send the read and write snapshot request to the Ceph based on the rbd-nbd process corresponding to the network block device when the Ceph client detects a read and write snapshot request to the snapshot database of the network block device Cluster to obtain the snapshot data fed back by the Ceph cluster in response to the read-write snapshot request;

An obtaining module, used to obtain the type of the read-write snapshot request;

A write module, configured to perform a write operation in the rbd-nbd process according to the write type when the type of the read-write snapshot request is a write request type to obtain write data;

The feedback module is used to feed back the write data and the snapshot data to the network block device to start the snapshot database in the network block device.
The device for reading and writing a snapshot of a network block device according to claim 15, wherein the writing module comprises:

The first determining unit is configured to determine whether the cache in the rbd-nbd process is empty if the type of the read-write snapshot request is the type of the write request;

The first obtaining unit is configured to obtain a first key value carried in the write request if the cache in the rbd-nbd process is not empty, wherein the first key value includes a write position and a write length information;

A comparison unit, configured to compare the first key value with the second key value in the cached entry in the cache;

The adding unit is configured to add a new cache entry in the cache if the first key value is less than or equal to the second key value, and store the requested content of the write request in the new cache entry.
A network block device snapshot reading and writing device, characterized in that the network block device snapshot reading and writing device includes: a memory, a processor, a communication bus, and a network block device snapshot reading and writing method readable instructions stored on the memory ,

The communication bus is used to realize the communication connection between the processor and the memory;

The processor is configured to execute the readable instructions of the network block device snapshot reading and writing method, so as to realize the steps of the network block device snapshot reading and writing method according to claim 1.
A network block device snapshot reading and writing device, characterized in that the network block device snapshot reading and writing device includes: a memory, a processor, a communication bus, and a network block device snapshot reading and writing method readable instructions stored on the memory ,

The communication bus is used to realize the communication connection between the processor and the memory;

The processor is configured to execute the readable instructions of the network block device snapshot reading and writing method to implement the steps of the network block device snapshot reading and writing method according to claim 2.
A storage medium, wherein the storage medium stores readable instructions of a network block device snapshot read and write method, and the readable instructions of the network block device snapshot read and write method are executed by a processor as described in claim 1. The steps of the network block device snapshot read and write method.
A storage medium, wherein the storage medium stores readable instructions of a network block device snapshot reading and writing method, and the readable instructions of the network block device snapshot reading and writing method are implemented as described in claim 2 when executed by a processor. The steps of the network block device snapshot read and write method. To