CN102843435A - Access and response method and access and response system of storing medium in cluster system - Google Patents

Abstract

The invention provides a storage medium access and response method and system in a cluster system. The access system includes: the cluster system includes a plurality of clients, wherein each client accesses the storage system in the cluster system through the InfiniBand network, wherein the client includes: an encapsulation device, used for receiving the client in the storage system When the small computer system interface SCSI protocol read/write command of a certain directory on a certain storage space, the read/write command is encapsulated into the first data packet of the remote direct storage access protocol SRP; the sending device is used to send to the storage system Sending the first data packet; the decapsulating device is used to decapsulate the information in the second data packet into SCSI protocol information after receiving the second data packet encapsulated by the SRP protocol fed back by the storage system to the first data packet ; The output device is used to output SCSI protocol information.

Description

A storage medium access and response method and system in a cluster system

technical field

The invention relates to the field of network communication, in particular to a storage medium access and response method and system in a cluster system.

Background technique

BTA was established in 1999, led by Compaq, Hewlett-Packard, IBM, Dell, Intel, Microsoft and Sun, to jointly research and develop high-speed advanced I/O standards. Originally named System I/O, in October 1999, it was officially renamed InfiniBand (abbreviated as IB). InfiniBand is a long cable connection method with high-speed, low-latency transmission characteristics. Compared with other network protocols (such as TCP/IP), InfiniBand has higher transmission efficiency. The reason is that many network protocols have the ability to forward lost data packets, but due to continuous confirmation and retransmission, communication based on these protocols will also slow down, which greatly affects performance. The TCP protocol is a widely used transport protocol, which can be seen in everything from refrigerators to supercomputers, but using it has to pay a high price: the TCP protocol is extremely complex, the code is huge, and it is full of Various special cases, and it is difficult to unload (the so-called unloading is not to occupy the running time of the CPU). In contrast, InfiniBand uses a trust-based, flow-control mechanism to ensure the integrity of the connection, and data packets are rarely lost. With InfiniBand, data is not transmitted until the receive buffer is confirmed to have sufficient space. After the data transmission is completed, the receiver returns a credit to indicate the availability of the cache space. In this way, InfiniBand eliminates the retransmission delay caused by the original packet loss, thereby improving efficiency and overall performance.

In terms of bandwidth, InfiniBand also has an advantage over FC solutions, where InfiniBand bandwidth is 40Gbps, while FC is only 16Gbps. The IB network is a brand-new open interconnection structure standard based on channels and switches. It has the characteristics of high bandwidth and low delay. The maximum theoretical bandwidth of the IB network can reach 120Gb/s. The current commonly used IB product is QDR equipment, its single-port unidirectional bandwidth is 40Gb/s, the minimum delay is less than 1μs, supports multiple transmission services, and supports remote memory direct access (RDMA, including RDMA read and RDMA write), so that data can Bypass the core to achieve "zero-copy" transfer.

In the field of high-performance computing, as more and more nodes of high-performance computers are connected by infiniband, it is more important whether SAN (Storage Area Network, storage area network) storage devices support seamless connection to infiniband networks.

Contents of the invention

The present invention provides a method and system for accessing and responding to storage media in a cluster system, and the technology to be solved

In order to solve the problems of the technologies described above, the present invention provides the following technical solutions:

An access system for storing media in a cluster system, the cluster system includes a plurality of clients, wherein each client accesses a storage system in the cluster system through an InfiniBand network, wherein the clients include:

The encapsulation device is used to encapsulate the read/write command into a remote direct storage access protocol when receiving a read/write command of the small computer system interface SCSI protocol of a certain directory on a certain storage space on the storage system by the client The first data packet of the SRP, wherein the first data packet carries the identification information of the client and the storage location information corresponding to the directory to be read/written by the read/write command on the storage system;

a sending device, connected to the encapsulating device, and configured to send the first data packet to the storage system;

The decapsulating device is configured to decapsulate the information in the second data packet into SCSI protocol information after receiving the second data packet encapsulated by the SRP protocol fed back by the storage system to the first data packet;

The output device is connected with the decapsulation device and is used for outputting the information of the SCSI protocol.

Preferably, the system also has the following characteristics: the system also includes:

The application device is used to apply to the storage system for the storage space of the client when the system is initialized;

The obtaining device is connected with the application device and is used to obtain the storage space allocated by the storage system for the client;

The configuration device is connected with the obtaining device and the packaging device, and is used for configuring the mapping relationship between the catalog of the client and the allocated storage space according to the allocated storage space.

Preferably, the system also has the following feature: the identification information of the client is the identification information of the InfiniBand communication network card on the client.

A response system for storing media in a cluster system, where the cluster system includes a plurality of clients, wherein each client accesses a storage system in the cluster system through an InfiniBand network, wherein the storage system includes:

The decapsulation device is used to decapsulate the information in the first data packet when receiving the first data packet of the SRP protocol through the InfiniBand network to obtain the read/write command of the SCSI protocol, wherein the read/write command Including the user's read/write commands for a certain directory on a certain storage space;

an output device, connected to the decapsulation, for informing the storage system to process the read/write command;

An encapsulating device, configured to encapsulate the SCSI information into a second data packet of the SRP protocol after receiving the SCSI information fed back by the storage system to the first data packet;

A sending device, connected to the encapsulating device, for sending the second data packet.

Preferably, the system also has the following characteristics: the system also includes:

The allocating device is configured to allocate to the client the storage space that the client can use after receiving the request from the client for applying for the storage space;

Notifying means, connected to the allocating means, for notifying the client of the storage space that the client can use.

A method for accessing storage media in a cluster system, where the cluster system includes a plurality of clients, wherein each client accesses a storage system in the cluster system through an InfiniBand network, wherein the client performs the following steps:

When receiving the read/write command of the small computer system interface SCSI protocol of a certain directory on a certain storage space on the storage system, the read/write command is encapsulated into the first data of the remote direct storage access protocol SRP packet, wherein the first data packet carries the identification information of the client and the storage location information corresponding to the directory to be read/written by the read/write command on the storage system;

sending the first data packet to the storage system;

After receiving the second data packet encapsulated by the SRP protocol fed back by the storage system to the first data packet, decapsulating the information in the second data packet into SCSI protocol information;

Output information about the SCSI protocol.

Preferably, the method also has the following characteristics: the method also includes:

When the system is initialized, apply to the storage system for the storage space of the client;

Obtain the storage space allocated by the storage system for the client;

According to the allocated storage space, configure the mapping relationship between the directory of the client and the allocated storage space.

Preferably, the method also has the following characteristics: the identification information of the client is the identification information of the InfiniBand communication network card on the client.

A method for responding to storage media in a cluster system, where the cluster system includes a plurality of clients, wherein each client accesses a storage system in the cluster system through an InfiniBand network, wherein the storage system performs the following steps:

When the first data packet of the SRP protocol is received through the InfiniBand network, the information in the first data packet is decapsulated to obtain the read/write command of the SCSI protocol, wherein the read/write command includes the Read/write commands for a certain directory on the space;

Notifying the storage system to process the read/write command;

After receiving the SCSI information fed back by the storage system to the first data packet, encapsulating the SCSI information into a second data packet of the SRP protocol;

Send the second data packet.

Preferably, the method also has the following characteristics: the method also includes:

After receiving the request from the client to apply for the storage space, allocate the storage space that the client can use for the client;

Informing the client of the storage space that the client can use.

The technical solution provided by the present invention realizes data transmission through InfiniBand and realizes "zero-copy" transmission.

Description of drawings

FIG. 1 is a schematic flow diagram of an embodiment of a storage medium access system in a cluster system provided by the present invention;

FIG. 2 is a schematic structural diagram of an embodiment of a response system for storage media in a cluster system provided by the present invention;

FIG. 3 is a schematic flowchart of an embodiment of a storage medium access method in a cluster system provided by the present invention;

FIG. 4 is a schematic flowchart of an embodiment of a storage medium response method in a cluster system provided by the present invention.

Detailed ways

In order to make the purpose, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that, in the case of no conflict, the embodiments in the present application and the features in the embodiments can be combined arbitrarily with each other.

FIG. 1 is a schematic flowchart of an embodiment of a storage medium access system in a cluster system provided by the present invention. The cluster system includes a plurality of clients, wherein each client accesses a storage system in the cluster system through an InfiniBand network, wherein the clients include:

The encapsulating device 101 is configured to encapsulate the read/write command into a remote direct storage access when receiving a read/write command of the small computer system interface SCSI protocol of a certain directory on a certain storage space on the storage system by the client The first data packet of the protocol SRP, wherein the first data packet carries the identification information of the client and the storage location information corresponding to the directory to be read/written by the read/write command on the storage system;

A sending device 102, connected to the encapsulating device 101, configured to send the first data packet to the storage system;

The decapsulating device 103 is configured to decapsulate the information in the second data packet into SCSI protocol information after receiving the second data packet encapsulated by the SRP protocol fed back by the storage system to the first data packet;

The output device 104 is connected with the decapsulation device 103 and configured to output the information of the SCSI protocol.

Of course, the storage space that each client device can use on the storage system can be pre-configured, or can be obtained by the client application. For example, the system also includes:

The application device is used to apply to the storage system for the storage space of the client when the system is initialized;

The obtaining device is connected with the application device and is used to obtain the storage space allocated by the storage system for the client;

The configuration device is connected with the obtaining device and the packaging device, and is used for configuring the mapping relationship between the catalog of the client and the allocated storage space according to the allocated storage space.

Wherein, the identification information of the client is the identification information of the InfiniBand communication network card on the client.

It can be seen from the above that since the storage space accessed by the client is not local, but connected by the IB network, when the client is initialized, the client initiates an application to the storage system, and the client applies to the storage system on the client. The storage space that can be used; when the user initiates a read/write command on the client, by encapsulating the internal read/write command of the client into the first data packet that can be transmitted on the IB network, the read/write command can be It is transmitted to the storage system through the IB network, and after receiving the second data packet fed back by the storage system, the data that can be parsed by the client is obtained by encapsulating the second data packet, thereby completing the storage system. access operations.

FIG. 2 is a schematic structural diagram of an embodiment of a storage medium response system in a cluster system provided by the present invention. In the method embodiment shown in Figure 2, the cluster system includes a plurality of clients, wherein each client accesses a storage system in the cluster system through an InfiniBand network, wherein the storage system includes:

The decapsulating device 201 is used to decapsulate the information in the first data packet when receiving the first data packet of the SRP protocol through the InfiniBand network to obtain a read/write command of the SCSI protocol, wherein the read/write Commands include the user's read/write commands for a certain directory on a certain storage space;

an output device 202, connected to the decapsulation 201, and configured to notify the storage system to process the read/write command;

The encapsulating device 203 is configured to, after receiving the SCSI information fed back by the storage system for the first data packet, encapsulate the SCSI information into a second data packet of the SRP protocol;

The sending device 204 is connected to the encapsulating device and configured to send the second data packet.

Optionally, the system also includes:

The allocating device is configured to allocate to the client the storage space that the client can use after receiving the request from the client for applying for the storage space;

Notifying means, connected to the allocating means, for notifying the client of the storage space that the client can use.

In the same way, since the storage space accessed by the client is not with the client used by the user, but is connected by the IB network, when the client is initialized, according to the application initiated by the client, the client is allocated The storage space that the client can use; when receiving the first data packet from the IB network, wherein the first data packet carries a read/write command, by decapsulating the first data packet into information that the storage system can parse , so that the storage system can process the read/write command. When the processing is completed, the processing result is encapsulated into a second data packet that can be transmitted on the IB network, so that the processing structure can be transmitted to the client through the IB network, thereby completing The response to the client's access.

The providing response system provided by the present invention is further described below:

The disk array is of great significance to the storage and processing of massive information, the availability and performance of data, and the target device provides device mapping and device access interface for the host. This paper designs and implements the target device of the SRP protocol. The SRP (SCSI RDMA protocol, remote direct storage access protocol) is also called the SCSI Remote Protocol. Its main function is to run the commands and data of the SCSI protocol on the infiniband through RDMA. On the network, it uses RDMA communication services to operate. The RDMA communication service provides communication between consumer pairs, using messages to pass control information and using RDMA read/write operations to transfer data.

Authorized access to logical resources of the storage system is achieved through the host HCA card GUID (Globally Unique Identifier, globally unique identifier). The HCA card is the Mellanox ConnectX IB InfiniBand Host Channel Adapter (HCA) card launched by Mellanox. The following is for the target The processing flow of read/write requests is introduced:

The above response system can be realized through srp target, which organically combines the infiniband protocol stack with the srp protocol. Using the srp storage protocol technology can take advantage of the high bandwidth and low delay characteristics of the infiniband network, so as to realize the transmission of io traffic from the client to the The disk array function makes SAN storage devices compatible with infiniband networks.

The following is an explanation from the perspective of software implementation:

The system architecture includes: infiniband protocol stack, srp protocol module and scsi command analysis module, in which:

The infiniband protocol stack provides the hardware drivers and services of the infiniband HBA card, so that the Srp protocol relies on it to establish Infiniband connections and read/write data;

The srp protocol module provides functions such as infiniband client connection management, srp read/write function realization, etc.;

The scsi command parsing module provides parsing of scsi commands.

In the architecture, the Srp target device has three interfaces, one is to communicate with the back-end logical volume manager to read or write IO data from the back-end device, one is to communicate with the plug and play manager, and the other is to communicate with the plug and play manager. For data transmission with the Initiator side. Connecting with the back-end logical volume manager is to write the received data into the back-end disk, or read the required data from the back-end disk, and transmit it to the initiator side through RDMA operation.

The Srp target relies on the infiniband access Layer to establish an Infiniband connection. First, it establishes a listening interface to receive connection requests from the Initiator, receive information units (IUs) from the Initiator, interpret and process the information units, and send corresponding responses to Initiator side. Its main function is to convert the received IU unit into a SCSI request, and encapsulate the processing result into an SRP information unit and send it to the client. It can provide services for several initiators at the same time, and can provide I/O processing for each initiator at the same time.

The third interface is the plug and play manager. When srpt starts, it will immediately register with the plug and play manager to provide an entry function for the notification callback, so it can be notified when there are new IB events.

The following describes the process of realizing this architecture with a specific example for the content of the present invention.

As described in the summary of the invention, the architecture of the present invention mainly includes: infiniband protocol stack (1), srp protocol module (2), scsi command analysis module (3)

The Srpt target device has three interfaces, one is to communicate with the back-end logical volume manager to read or write IO data from the back-end device, one is to communicate with the plug and play manager, and the other is used to communicate with the Initiator-side data transmission. Connecting with the back-end logical volume manager is to write the received data into the back-end disk, or read the required data from the back-end disk, and transmit it to the initiator side through RDMA operation.

The Srp target relies on the infiniband access Layer to establish an Infiniband connection. First, it establishes a listening interface to receive connection requests from the Initiator, receive information units (IUs) from the Initiator, interpret and process the information units, and send corresponding responses to Initiator side. Its main function is to convert the received IU unit into a SCSI request, and encapsulate the processing result into an SRP information unit and send it to the client. It can provide services for several initiators at the same time, and can provide I/O processing for each initiator at the same time.

The third interface is the plug and play manager. When srpt starts, it will immediately register with the plug and play manager to provide an entry function for the notification callback, so it can be notified when there are new IB events.

The Srp target driver is event-driven, and all its behaviors are responses to certain events. Common events include RDMA sending messages, RDMA receiving messages, RDMA read operations, and RDMAwrite operations.

First, the implementation of the read operation is explained:

The read operation refers to the process in which the SRP initiator server reads information from the SRP Target server. The read operation includes the SRP initiator obtaining SCSI storage device information from the SRP Target server, checking the capacity of the storage device, and reading the data of the storage device. The process of reading data by the client is as follows:

1) Infiniband completes the call of the queue callback function and takes out the completed work request from the system queue. If the status of the work request is wrong, abort the wrong SCSI command and perform error handling, otherwise go to 2

2) If the operation type is to receive a message, determine the command type of the received SRP, set the RDMA triplet information, obtain the SCSI command attribute, explain the SCSI command, allocate and process the SCSI command structure, set the tag of the command,

3) Allocate corresponding resources for SCSI commands, judge SCSI command operations, allocate data buffers, perform SCSI read operations, and read data from devices

4) Obtain RDMA channel, set and allocate RDMA buffer area, and perform RDMA write operation

5) Create an RSP response packet and use the RDMA SEND operation to send the message

6) The RDMA SEND message is completed, the RDMA buffer area is released, and a new work request is delivered.

The implementation of the write operation is described below:

The write operation refers to the process in which the SRP initiator writes data to the SRP Target. The process of writing data by the client is as follows:

1) Infiniband completes the call of the queue callback function and takes out the completed work request from the system queue. If the status of the work request is wrong, abort the wrong SCSI command and perform error handling, otherwise go to 2

2) If the operation type is to receive a message, determine the command type of the received SRP, set the RDMA triplet information, obtain the SCSI command attribute, explain the SCSI command, allocate and process the SCSI command structure, set the tag of the command,

3) Allocate corresponding resources for SCSI commands, judge SCSI command operations, allocate data buffers, set RDMA channel read mode, and start RDMA read operations

4) After the RDMA read callback function is completed, set the SCSI command status to data pending status, and write the read data to the back-end disk

5) Create an RSP response packet and use the RDMA SEND operation to send the message

6) The RDMA SEND message is completed, the RDMA buffer area is released, and a new work request is delivered.

So far, the read/write process of the srp target has been fully realized. This technology allows the disk array to use the infiniband network to transmit data.

Therefore, using this technology, the target device makes the performance of the infiniband network fully utilized, and the overall performance bandwidth of the system is close to the limit of the infiniband theory.

FIG. 3 is a schematic flowchart of an embodiment of a storage medium access method in a cluster system provided by the present invention. In the method embodiment shown in Figure 3, the cluster system includes a plurality of clients, wherein each client accesses a storage system in the cluster system through the InfiniBand network, wherein the client performs the following steps:

Step 301, when receiving the read/write command of the small computer system interface SCSI protocol of a certain directory on a certain storage space on the storage system by the client, the said read/write command is encapsulated into a remote direct storage access protocol SRP A first data packet, wherein the first data packet carries the identification information of the client and the storage location information corresponding to the directory to be read/written by the read/write command on the storage system;

Step 302, sending the first data packet to the storage system;

Step 303: After receiving the second data packet encapsulated by the SRP protocol fed back by the storage system to the first data packet, decapsulate the information in the second data packet into SCSI protocol information;

Step 304, output the information of the SCSI protocol.

Optionally, the method also includes:

When the system is initialized, apply to the storage system for the storage space of the client;

Obtain the storage space allocated by the storage system for the client;

According to the allocated storage space, configure the mapping relationship between the directory of the client and the allocated storage space.

Optionally, the identification information of the client is the identification information of the InfiniBand communication network card on the client.

It can be seen from the above that since the storage space accessed by the client is not local, but connected by the IB network, when the client is initialized, the client initiates an application to the storage system, and the client applies to the storage system on the client. The storage space that can be used; when the user initiates a read/write command on the client, by encapsulating the internal read/write command of the client into the first data packet that can be transmitted on the IB network, the read/write command can be It is transmitted to the storage system through the IB network, and after receiving the second data packet fed back by the storage system, the data that can be parsed by the client is obtained by encapsulating the second data packet, thereby completing the storage system. access operations.

FIG. 4 is a schematic flowchart of an embodiment of a storage medium response method in a cluster system provided by the present invention. The method embodiment shown in Fig. 4 comprises that the cluster system includes a plurality of clients, wherein each client accesses a storage system in the cluster system through an InfiniBand network, wherein the storage system performs the following steps:

Step 401, when receiving the first packet of the SRP protocol through the InfiniBand network, decapsulate the information in the first packet to obtain the read/write command of the SCSI protocol, wherein the read/write command includes the Read/write commands for a certain directory on a certain storage space;

Step 402, notify the storage system to process the read/write command;

Step 403, after receiving the SCSI information fed back by the storage system for the first data packet, encapsulating the SCSI information into a second data packet of the SRP protocol;

Step 404, sending the second data packet.

Optionally, the method also includes:

After receiving the request from the client to apply for storage space, assign the client to the client

Since the storage space accessed by the client is not with the client used by the user, but is connected by the IB network, when the client is initialized, the client is assigned the client according to the application initiated by the client. The storage space that can be used; when the first data packet is received from the IB network, wherein the first data packet carries a read/write command, by decapsulating the first data packet into information that the storage system can parse, so that The storage system can process the read/write command, and when the processing is completed, encapsulate the processing result into a second data packet that can be transmitted on the IB network, so that the processing structure can be transmitted to the client through the IB network, thereby completing the The response to the visit.

The above is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Anyone skilled in the art can easily think of changes or substitutions within the technical scope disclosed in the present invention. Should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope described in the claims.

Claims (10)

1. the access system of a storage medium in group system is characterized in that, group system comprises a plurality of clients, and wherein all through the storage system in the said group system of InfiniBand access to netwoks, wherein said client comprises each client:

Packaging system; Be used for when receiving client on storage system on a certain memory space during read/write command of the small computer system interface SCSI agreement of a certain catalogue; Said read/write command is packaged into first packet of long-range direct memory access protocols SRP, and identification information and this read/write command that wherein said first packet carries said client wanted read/write catalogue corresponding stored position information on storage system;

Dispensing device links to each other with said packaging system, is used for sending said first packet to said storage system;

De-encapsulating devices is used for after receiving second packet of storage system to the employing SRP protocol encapsulation of said first packet feedback, the information deblocking in said second packet being dressed up the information of SCSI agreement;

Output device links to each other with said de-encapsulating devices, is used to export the information of said SCSI agreement.

2. system according to claim 1 is characterized in that, said system also comprises:

The application device is used for when system initialization, to the memory space of this client of storage system application;

Deriving means links to each other with said application device, is used to obtain the memory space that storage system is distributed for this client;

Inking device links to each other with said packaging system with said deriving means, is used for according to the memory space that distributes, and disposes the catalogue of this client and the mapping relations of assigned memory space.

3. system according to claim 1 is characterized in that, the identification information of said client is the identification information of InfiniBand communication network interface card on this client.

4. the responding system of a storage medium in group system is characterized in that, group system comprises a plurality of clients, and wherein all through the storage system in the said group system of InfiniBand access to netwoks, wherein said storage system comprises each client:

De-encapsulating devices; Be used for when receiving first packet of SRP agreement through the InfiniBand network; With the information decapsulation in said first packet, obtain the read/write command of SCSI agreement, wherein said read/write life comprises the read/write command of user's a certain catalogue on a certain memory space;

Output device links to each other with said decapsulation, is used to notify storage system to handle said read/write command;

Packaging system is used for after receiving the SCSI information of storage system to said first packet feedback, said SCSI information being packaged into second packet of SRP agreement;

Dispensing device links to each other with said packaging system, is used to send said second packet.

5. system according to claim 4 is characterized in that, said system also comprises:

Distributor is used for after the request that receives client application memory space, the memory space that distributes this client to use for this client;

Notifying device links to each other with said distributor, is used to notify the said client memory space that this client can be used.

6. the access method of a storage medium in group system; It is characterized in that; Group system comprises a plurality of clients, and wherein each client is all through the storage system in the said group system of InfiniBand access to netwoks, wherein said client executing following steps:

When receiving client on storage system on a certain memory space during read/write command of the small computer system interface SCSI agreement of a certain catalogue; Said read/write command is packaged into first packet of long-range direct memory access protocols SRP, and identification information and this read/write command that wherein said first packet carries said client wanted read/write catalogue corresponding stored position information on storage system;

Send said first packet to said storage system;

After receiving second packet of storage system, the information deblocking in said second packet is dressed up the information of SCSI agreement to the employing SRP protocol encapsulation of said first packet feedback;

Export the information of said SCSI agreement.

7. method according to claim 6 is characterized in that, said method also comprises:

When system initialization, to the memory space of this client of storage system application;

Obtain the memory space that storage system is distributed for this client;

According to the memory space that distributes, dispose the catalogue of this client and the mapping relations of assigned memory space.

8. method according to claim 6 is characterized in that, the identification information of said client is the identification information of InfiniBand communication network interface card on this client.

9. the response method of a storage medium in group system; It is characterized in that; Group system comprises a plurality of clients, and wherein each client is all through the storage system in the said group system of InfiniBand access to netwoks, and wherein said storage system is carried out following steps:

When receiving first packet of SRP agreement through the InfiniBand network; With the information decapsulation in said first packet; Obtain the read/write command of SCSI agreement, wherein said read/write life comprises the read/write command of user's a certain catalogue on a certain memory space;

The notice storage system is handled said read/write command;

After receiving the SCSI information of storage system, said SCSI information is packaged into second packet of SRP agreement to said first packet feedback;

Send said second packet.

10. method according to claim 9 is characterized in that, said method also comprises:

After the request that receives client application memory space, the memory space that distributes this client to use for this client;

Notify the said client memory space that this client can be used.

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