WO2021018086A1

WO2021018086A1 - Method and apparatus for communication between storage devices, storage medium and storage device

Info

Publication number: WO2021018086A1
Application number: PCT/CN2020/104802
Authority: WO
Inventors: 朱维国; 郭金生
Original assignee: 中兴通讯股份有限公司
Priority date: 2019-07-31
Filing date: 2020-07-27
Publication date: 2021-02-04
Also published as: CN112311743A

Abstract

Provided herein are a method and apparatus for communication between storage devices, a storage medium and a storage device, wherein the method comprises: at phase 1, a first storage device acts as a boot device and sends a small computer system interface (SCSI) command to a second storage device, wherein a SELECT REPORT field of the SCSI command is set to a specific value, and the specific value is used to instruct the second storage device to create a virtual logical unit; and the first storage device receives response data fed back by the second storage device so as to establish a first communication connection between the first storage device and the second storage device, the response data carrying information of the virtual logical unit. At phase 2, the second storage device acts as as the boot device and completes the establishment of a second communication connection with the first storage device in accordance with the same method as in phase 1. Phase 1 and phase 2 may occur simultaneously or sequentially.

Description

Communication method, device, storage medium and storage device between storage devices

This article claims the priority of the Chinese patent application CN201910706345.1 entitled "A method, device, storage medium and storage device for communication between storage devices" filed on July 31, 2019, the entire content of which is incorporated herein by reference .

Technical field

This article relates to the field of communications, and in particular to a method, device, storage medium and storage device for communication between storage devices.

Background technique

Currently, there are multiple transmission media for communication between storage devices, and the transmission protocols corresponding to these transmission media are also different. For example, optical fiber corresponds to the Fiber Channel (FC) protocol, and Ethernet corresponds to the Internet Small Computer System Interface (iSCSI) protocol. A commonly used communication method is to package and unpack the management data in the sending device and the receiving device according to the requirements of the protocol (FC protocol or iSCSI and other protocols) to realize the transmission of the management data between storage devices.

The problem with the above method is that its implementation is strongly related to the underlying protocol type, and needs to adapt to different underlying protocol types, such as FC, iSCSI and other protocols, and the processing is complicated.

Summary of the invention

The embodiments herein provide a communication method, apparatus, storage medium, and storage device between storage devices to solve the problem that the communication between storage devices in related technologies is strongly related to the underlying protocol type and needs to adapt to different underlying protocol types.

In order to solve the above-mentioned problems, the technical solutions of the embodiments herein are implemented as follows: A communication method between storage devices includes: a first storage device sends a first small computer system interface SCSI command to a second storage device, wherein the first SCSI The SELECT REPORT field of the command is set to a first specific value, and the first specific value is used to instruct the second storage device to create a first virtual logical unit; the first storage device receives the second storage device The first response data fed back to establish a first communication connection between the first storage device and the second storage device, wherein the first response data carries the information of the first virtual logical unit; The first storage device receives the second SCSI command sent by the second storage device, wherein the SELECT REPORT field of the second SCSI command is set to a second specific value; the first storage device is based on the second A specific value creates a second virtual logical unit; the first storage device sends second response data to the second storage device to establish a second communication connection between the first storage device and the second storage device, Wherein, the second response data carries information of the second virtual logical unit.

Further, the value range of the first specific value and the second specific value is F8h to FFh, and the value range of the first SCSI command code and the second SCSI command code is C0h to FFh.

The embodiment of this document also provides a communication device between storage devices, which is set in a first storage device, and includes: a sending module for sending a first SCSI command to a second storage device, wherein the SELECT of the first SCSI command The REPORT field is set to a first specific value, the first specific value is used to instruct the second storage device to create a first virtual logical unit; a receiving module is used to receive the first response data fed back by the second storage device , To establish a first communication connection between the first storage device and the second storage device, wherein the first response data carries the information of the first virtual logical unit; the receiving module also uses After receiving the second SCSI command sent by the second storage device, the SELECT REPORT field of the second SCSI command is set to a second specific value; the creation module is configured to create a second SCSI command according to the second specific value. Virtual logic unit; the sending module is also used to send second response data to the second storage device to establish a second communication connection between the first storage device and the second storage device, where all The second response data carries information of the second virtual logical unit.

The embodiments herein also provide a storage device including a memory and a processor, wherein a computer program is stored in the memory, and the processor executes the computer program to implement any of the above methods.

The embodiments herein also provide a computer-readable storage medium that stores computer-executable instructions, and the computer-executable instructions are configured to perform any of the methods described above.

Description of the drawings

FIG. 1 is a flowchart of a communication method between storage devices according to the first embodiment of this document;

2 is a block diagram of a communication device between storage devices according to the second embodiment of this document;

3 is a block diagram of another communication device between storage devices according to the second embodiment of this document;

4 is a block diagram of another communication device between storage devices according to the second embodiment of this document;

5 is a block diagram of a communication system between storage devices according to the third embodiment of this document;

6 is a schematic diagram of a SCSI command report logical unit REPORT LUNS provided in the fourth embodiment of this document;

Figure 7 is a schematic diagram of an interface parameter defined in the fourth embodiment of this document;

Figure 8 is a schematic diagram of a SCSI command defined in the fourth embodiment of this document;

Fig. 9 is a cooperative flow chart of a service communication between storage devices provided in the fourth embodiment of this document.

Detailed ways

In the following, the technical solution of this document will be further described in detail through the accompanying drawings and embodiments. It should be noted that the "first" and "second" in the text are only used for distinction and do not indicate the order of sequence. In addition, the solutions in the following embodiments can be combined arbitrarily without conflict.

Example one

Embodiment 1 of this document provides a communication method between storage devices. Fig. 1 is a flow chart of a communication method between storage devices according to the first embodiment of this document. As shown in Fig. 1, the method includes the following steps: S102, a first storage device sends a first SCSI command to a second storage device, wherein, The SELECT REPORT field of the first SCSI command is set to a first specific value, and the first specific value is used to instruct the second storage device to create a first virtual logical unit; S104, the first storage device receives the second storage device According to the first response data fed back by the first virtual logic unit, a first communication connection between the first storage device and the second storage device is established; S106, the first storage device receives the first storage device sent by the second storage device Two SCSI commands, where the SELECT REPORT field of the second SCSI command is set to a second specific value; S108, the first storage device creates a second virtual logical unit according to the second specific value; S110, the first storage device The second virtual logical unit is sent to the second storage device as second response data to establish a second communication connection between the first storage device and the second storage device.

Through the above method, a two-way connection is established between the two storage devices through the virtual logical unit, and subsequent communication can be normal, thereby shielding the influence of the transmission medium.

It should be noted that the process of establishing the first communication connection in S102-S104 and the process of establishing the second communication connection in S106-S110 can be performed synchronously or sequentially, and the sequence does not affect the implementation of the solution.

In an embodiment, after completing the second communication connection between the first storage device and the second storage device, the method further includes: the first storage device sends a first communication message to the second storage device, Wherein, the first communication message carries a first SCSI command code, and the first SCSI command code is used to indicate that the first communication message is a communication message between storage devices.

By setting the SCSI command code, the second storage device can recognize that the type of the current communication message is a communication message between storage devices.

In an embodiment, the first storage device sending the first communication message to the second storage device includes: the first storage device converts the service data to be sent into a SCSI command, and uses the SCSI command as the first communication message Send to the second storage device.

In an implementation manner, the conversion step may be to encapsulate the service data to be sent in a SCSI command carrying the first SCSI command code.

In an embodiment, after completing the second communication connection between the first storage device and the second storage device, the method further includes: the first storage device receives a second communication message sent by the second storage device , Wherein, the second communication message carries a second SCSI command code, and the second SCSI command code is used to indicate that the second communication message is an inter-storage device communication message; the first storage device parses according to a preset analysis method And read the second communication message.

The SCSI command set defines many standard commands. The SCSI command code is used to identify which SCSI command is. In addition to the well-defined standard SCSI command codes, the SCSI protocol also reserves a range of custom SCSI command codes for manufacturers, and we choose one of them as the command code within this range.

In the first embodiment of this document, the customized SCSI command code is used to identify the current communication message as a communication message between storage devices. In an actual application scenario, the storage device can recognize the command code, so as to parse the content of the communication data packet according to the corresponding analysis method.

In an embodiment, the value range of the first specific value and the second specific value is F8h to FFh, and the value range of the first SCSI command code and the second SCSI command code is C0h to FFh.

The above value range is the value range reserved by the standard for manufacturers. In the first embodiment herein, the first specific value and the second specific value may be the same or different, and the first SCSI command code and the second SCSI command code may be the same or different.

Example two

The second embodiment of this document provides a communication device between storage devices, which is set in the first storage device. FIG. 2 is a block diagram of a communication device between storage devices according to the second embodiment of this document. As shown in FIG. The communication device includes the following modules: a sending module 22 for sending a first SCSI command to a second storage device, where the SELECT REPORT field of the first SCSI command is set to a first specific value, and the first specific value is used to indicate The second storage device creates a first virtual logical unit; the receiving module 24 is used to receive the first response data fed back by the second storage device to establish a first communication connection between the first storage device and the second storage device , Wherein the first response data carries the information of the first virtual logical unit; the receiving module 24 is also used to receive the second SCSI command sent by the second storage device, where the SELECT REPORT of the second SCSI command The domain is set to a second specific value; the creation module 26 is used to create a second virtual logical unit according to the second specific value; the sending module 22 is also used to send second response data to the second storage device to establish A second communication connection between the first storage device and the second storage device, wherein the second response data carries information of the second virtual logical unit.

Through the above device, a two-way connection is established between the two storage devices by creating a virtual logical unit, and subsequent communication can be normal, thereby shielding the influence of the transmission medium.

In the second embodiment, the sending module 22 is further configured to send a first communication message to the second storage device, where the first communication message carries a first SCSI command code, and the first SCSI command code is used to indicate The first communication message is a communication message between storage devices.

Fig. 3 is a block diagram of another communication device between storage devices according to the second embodiment of this document. As shown in Fig. 3, the sending module 22 includes: a conversion sub-module 32 for converting service data to be sent into SCSI commands; The module 34 is configured to send the SCSI command as the first communication message to the second storage device.

In the second embodiment, the receiving module 24 is further configured to receive a second communication message sent by the second storage device, where the second communication message carries a second SCSI command code, and the second SCSI command code is used for Indicate that the second communication message is a communication message between storage devices.

FIG. 4 is a block diagram of another communication device between storage devices according to the second embodiment of this document. As shown in FIG. 4, the communication device between storage devices includes all the modules shown in FIG. 2 and also includes a parsing module 42 for Analyze and read the second communication message according to a preset analysis manner.

Example three

The third embodiment of this document provides a communication system between storage devices. Fig. 5 is a block diagram of a communication system between storage devices according to the third embodiment of this document. As shown in Fig. 5, the system includes a first storage device 52 and a second storage device 54: the first storage device 52 is used to communicate with the The second storage device sends the first SCSI command, where the SELECT REPORT field of the first SCSI command is set to a first specific value; the second storage device 54 is configured to receive the first SCSI command, and according to the first specific value Create a first virtual logical unit, and send the information of the first virtual logical unit as the first response data to the first storage device; the first storage device 52 is also used to receive the first response data to establish the The first communication connection between the first storage device and the second storage device; the second storage device 54 is also used to send a second SCSI command to the first storage device, where the SELECT REPORT field of the second SCSI command is Set to a second specific value; the first storage device 52 is also used to receive a second SCSI command, create a second virtual logical unit according to the second specific value, and use the information of the second virtual logical unit as a second response The data is sent to the second storage device; the second storage device 54 is also used to receive the second response data to establish a second communication connection between the first storage device and the second storage device.

Example four

The fourth embodiment of this document will be described below in combination with specific scenarios.

SCSI devices are divided into startup devices and target devices. The target device receives the request command from the boot device, analyzes the received SCSI command's operation code and other parameters, executes the corresponding processing according to the command operation code (ie the command code in the above embodiment), and sends it to the boot device after the processing is completed answer. The boot device and the target device here correspond to the first storage device and the second storage device in the foregoing embodiment.

In order to realize the transmission of SCSI commands between the starting device and the target device, according to the definition of SCSI, an I_T_L connection relationship (A nexus between a SCSI initiator port, a SCSI target port, and a logical unit) needs to be established between them, that is, SCSI start The connection between the device port, the SCSI target port and the logical unit.

The two storage devices are each other's boot device and target device. When they establish an I_T connection (A nexus between a SCSI initiator port and a SCSI target port), that is, the connection between the SCSI initiator port and the SCSI target port, the protocol is set up The specific fields in the virtual logic unit are automatically generated to establish the I_T_L connection relationship.

When two storage devices establish an I_T connection, they are divided into two stages.

In the first stage, one of the storage devices is used as the boot device. The boot device sends the SCSI command to report the logical unit REPORT LUNS to scan the target device for the logical unit. In the fourth embodiment of this document, the SELECT REPORT field of the command is set to a specific value. After the target device receives the REPORT LUNS command, it checks the SELECT REPORT field of the command. If it is the specific value, the target device will automatically create a virtual logical unit and use the relevant information of the virtual logical unit as the response data of the REPORT LUNS command. Sent to the boot device, the boot device can recognize the logic unit. This completes the establishment of the first I_T_L connection relationship between the boot device and the target device. The virtual logical unit does not occupy any actual storage space.

Here, the purpose of creating a virtual logical unit is to establish a communication basis for SCSI commands, because SCSI command interaction is based on logical units.

In one embodiment, when the boot device sends the SCSI command REPORT LUNS, the SELECT REPORT field of the command is set to 0xFF; when the target device receives the REPORT LUNS command, it checks the SELECT REPORT field. If its value is 0xFF, the SELECT REPORT field is set in the target device Create a virtual logical unit and use the related information of the virtual logical unit as the response data of the REPORT LUNS command. Fig. 6 is a schematic diagram of a SCSI command REPORT LUNS provided in the fourth embodiment of this document.

The value range of the SELECT REPORT field is from F8h to FFh, and the specific value is customized by the manufacturer. The value of the fourth embodiment of this document is 0xFF.

In the second stage, the target device in the first stage serves as the initiating device in the second stage to initiate an I_T connection establishment request to the initiating device in the first stage (the target device in the second stage). The subsequent processing of this stage is the same as that of stage one. Specifically, the startup device in phase two sends a SCSI command to report the logical unit REPORT LUNS to scan the logical unit of the target device in phase two. The fourth embodiment of this document sets the SELECT REPORT field of the command to a specific value. After receiving the REPORT LUNS command, the target device in phase two checks the SELECT REPORT field of the command. If it is a specific value, the target device in phase two creates a virtual logical unit and uses the relevant information of the virtual logical unit as REPORT LUNS With the response data of the command, the starting device of stage two can recognize the logical unit, thus completing the establishment of the second I_T_L connection relationship between the starting device of stage two and the target device of stage two.

The role of phase two is to establish a "reverse" I_T connection. That is, the initiator of phase one is used as the target of phase two, and the target of phase one is used as the initiator of phase two. This forms the basis for two-way communication.

It should be noted that the establishment of the first I_T_L connection relationship and the second establishment of the I_T_L connection relationship can be performed simultaneously or sequentially, and the sequence does not affect the implementation of the solution.

The fourth embodiment of this document provides a unified interface for services to send and receive messages. When the sender (starting device) service calls the sending interface, the interface parameters that need to be provided include the receiver (target device) identifier, message content, message length, and the definition of interface parameters is shown in Figure 7. Specifically, the sending end (initiating device) interface encapsulates the service message in the SCSI command of the custom command opcode, and sends the SCSI command to the virtual logical unit of the receiving end (target device) through the established I_T_L connection. After receiving the customized SCSI command, the receiving end (target device) parses the message content and performs corresponding processing.

The fourth embodiment of this document also defines the format of the SCSI command. Byte 0 is the custom SCSI command opcode 0xFE in the fourth embodiment of this article; the upper 4 bits of byte 1 are the version number, and the lower 4 bits are the magic number for verification; bytes 2-5 are the length of the transmitted data ( (In bytes); bytes 6-8 are reserved bytes; byte 9 is the control character defined by the SCSI protocol. As shown in Figure 8.

In one embodiment, the cooperation process of the communication between the storage devices of the business is shown in FIG. 9. At the sending end (starting device), the service calls the interface send_msg provided in the fourth embodiment of the method to send a message to the receiving end (target device), using the target device identifier, message length, and message content as interface parameters. Specifically, the transmitting end (initiating device) interface internally converts the service message into a custom SCSI command (command code is 0xFE), and sends the SCSI command to the receiving end (target device). The receiving end (target device) receives the SCSI command with a command code of 0xFE, parses the message content and performs corresponding processing.

The embodiments herein also provide a storage device, including a memory and a processor, the memory stores a computer program, and the processor is configured to run the computer program to execute the steps in any of the foregoing method embodiments.

The embodiments herein also provide a storage medium in which a computer program is stored, wherein the computer program is configured to execute the steps in any one of the foregoing method embodiments when running.

Through the above method, the communication between storage devices can not only shield the difference of the underlying transmission protocol, but also ensure simple and reliable use.

The above are only the embodiments of this article and are not used to limit this article. For those skilled in the art, this article can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of this article shall be included in the scope of the claims of this article.

Claims

A communication method between storage devices, which includes:

The first storage device sends the first SCSI command to the second storage device, wherein the SELECT REPORT field of the first SCSI command is set to a first specific value, and the first specific value is used to indicate the second storage device Create the first virtual logical unit;

The first storage device receives the first response data fed back by the second storage device to establish a first communication connection between the first storage device and the second storage device, wherein the first response data Carries the information of the first virtual logical unit;

Receiving, by the first storage device, a second SCSI command sent by the second storage device, wherein the SELECT REPORT field of the second SCSI command is set to a second specific value;

The first storage device creates a second virtual logical unit according to the second specific value;

The first storage device sends second response data to the second storage device to establish a second communication connection between the first storage device and the second storage device, wherein the second response data is Carry the information of the second virtual logical unit.
5. The method according to claim 1, wherein after the second communication connection between the first storage device and the second storage device is established, the method further comprises:

The first storage device sends a first communication message to the second storage device, where the first communication message carries a first SCSI command code, and the first SCSI command code is used to indicate the first communication The message is a communication message between storage devices.
3. The method of claim 2, wherein the first storage device sending the first communication message to the second storage device comprises:

The first storage device converts the service data to be sent into a SCSI command, and sends the SCSI command as the first communication message to the second storage device.
8. The method according to any one of claims 1 to 3, wherein after establishing a second communication connection between the first storage device and the second storage device, the method further comprises:

The first storage device receives a second communication message sent by the second storage device, where the second communication message carries a second SCSI command code, and the second SCSI command code is used to indicate the second The communication message is a communication message between storage devices;

The first storage device parses and reads the second communication message according to a preset analysis manner.
A storage device comprising a memory and a processor, wherein a computer program is stored in the memory, and the processor executes the computer program to implement the method according to any one of claims 1-4.
A computer-readable storage medium storing computer-executable instructions configured to execute the method according to any one of claims 1-4.
A communication device between storage devices, which is provided in a first storage device, and includes:

The sending module is configured to send a first SCSI command to a second storage device, wherein the SELECT REPORT field of the first SCSI command is set to a first specific value, and the first specific value is used to indicate the second storage The device creates the first virtual logical unit;

The receiving module is configured to receive the first response data fed back by the second storage device to establish a first communication connection between the first storage device and the second storage device, wherein the first response data is Carrying information of the first virtual logical unit;

The receiving module is further configured to receive a second SCSI command sent by the second storage device, wherein the SELECT REPORT field of the second SCSI command is set to a second specific value;

A creation module, configured to create a second virtual logical unit according to the second specific value;

The sending module is further configured to send second response data to the second storage device to establish a second communication connection between the first storage device and the second storage device, wherein the second response The data carries the information of the second virtual logical unit.
8. The apparatus of claim 7, wherein the sending module is further configured to send a first communication message to the second storage device, wherein the first communication message carries a first SCSI command code, and the The first SCSI command code is used to indicate that the first communication message is a communication message between storage devices.
The device according to claim 8, wherein the sending module comprises:

The conversion sub-module is used to convert the service data to be sent into SCSI commands;

The sending submodule is configured to send the SCSI command as the first communication message to the second storage device.
8. The apparatus according to any one of claims 7-9, wherein the receiving module is further configured to receive a second communication message sent by the second storage device, wherein the second communication message carries a second SCSI command code, where the second SCSI command code is used to indicate that the second communication message is an inter-storage device communication message.