TWI231671B - Method for interviewing logic equipment by Internet small computer systems interface (iSCSI) - Google Patents

Abstract

The present invention relates to a method for interviewing logic equipment by Internet small computer systems interface (iSCSI), which realizes the data transmission from the initiator to the logic target, comprising: giving each target equipment document a set of ID and logical unit numbers (LUN) and waiting the connection between the initiator and the target; after setting up the connection, accessing SCSI protocol data unit (PDU) from the connection; accessing SCSI command data block (CDB) for SCSI PDU; after confirming the ID in SCSI CDB with the corresponding LUN equipment documents, conducting the corresponding processes to the equipment documents in accordance with the SCSI instructions; sending the corresponding SCSI CDB back to the initiator from the connection.

Description

1231671 V. Description of the invention (1) [Technical field to which the invention belongs] The present invention relates to a method for implementing the i SCS I protocol, and particularly to a method for accessing a logical device using the iSCSI protocol. [Prior technology] i s c S I (Internet small computer system interface), i n t e r n e t S C S I, is a standard for data block transmission on the I η ΐ e r n e t protocol network, especially Ethernet. Fundamentally, the i SCS I protocol is a method of transmitting SCS I data blocks with short latency over the IP network. SCS I (Small Computer System Interface) is a widely used technology standard for connecting hard disks and computers. I SCS I is a technology that applies this technology to network connections. SCS I is a block-oriented client / server I / 0 protocol that communicates between physical devices (such as drives, printers, electronics, etc.). The device that sends an SCS I command is called the initiating device (Ini ti at or), that is, the party that sends the data access request, usually the server or the user's computer. The party that receives and responds to the request is the target, usually the storage device. The initiating device is responsible for sending a Command Data Block (CDB). The command data block contains parameters that must be executed by the target device receiving the CDB. SCSI transmitters map these CDB messages into physical interconnections to propagate this information. The initiating device sends the SCS I task to the target device to perform a 0s-level data 1 exclusive input operation. A target device has one or more logical units to process initiating device ^ request commands, and each logical unit is assigned a label number or logical unit number (LUN). Each logical unit containing the processing π order is contained in one, and is initiated by the initiating device

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V. Description of the invention (2) 1 I standard device specific logic unit transmission. For example: the initiator requests to read the data block, and the logic unit of the target device transmits the corresponding shell block to the sending device, and indicates that the request is completed & by the interrupt status. The main task of iSCsi is to complete CDB encapsulation and reliable transfer between the initiator and the target device through the P network. The iSCSI protocol realizes the transmission of SCSI commands on the TCP / IP network, so that users can access the block (b 1 0 c k) storage device on the server anywhere on the network through the most widely used Ethernet at present. These storage devices can be hard disks, CD-ROMs, or other hardware devices, but these devices must be capable of executing SCSI commands. First, in Linux, almost all hardware devices have their corresponding device = pieces, such as hard disks, CPUs, etc., and many generated devices such as redundant array of disks (Raid) will also have their corresponding device files . The Linux kernel talks to the process through device files, so device drivers in the kernel can communicate with the physical device or execute instructions through them.凊 Refer to “Figure 1”. Currently in UnuXT, the implementation methods of the 120 target devices of most of the 4 of this agreement are written as a Linux kernel module (kernel module), which is compiled and loaded into the kernel. The Ugly Module will act as a 12-shaped bridge between the network subsystem (Network Subsystem) and the SCSR system (SCSI Subsystem) in the kernel. The iSCSI protocol is a process of packetizing and unpacking on the network. At one end of the network, the data packet is encapsulated into three parts: Tcp / I, packet and scsm, and the other part of the content is transmitted sequentially to the network. Untie. 11231671 V. Description of the invention (3) First obtain the iSCSI PDU (Protocol Data Unit) from the initiator u 0 from the network subsystem 1 2 1 and then do the corresponding according to the different i SCS I commands in the PDU. Process and respond, and then return to the network subsystem 121. Many PDUs contain SCSI CDBs, and these CDBs will be submitted to the SCSI subsystem 1 23 for processing, and the processed responses will be transmitted in the form of CDB. The i SCS I module 1 2 2 will then do the related Process and then send these PDs to the network subsystem 12. Therefore, the current Module can only provide SCSI physical devices, such as drives, printers, computers, etc., to users for use. However, if the server is used for performance, fault tolerance, scalability, or convenient management purposes, some logical devices (or virtual devices) are usually constructed. , And want to provide these methods to users through Modu 1 e, which can not be done directly in the iSCSI protocol. [Summary of the invention] Here, the present invention is to solve the above problems by using i SCS The method of I protocol accessing logical devices is mainly to make the i SCS I protocol not only available to SCS I physical devices, but also to provide users with logical devices such as RAI D., logical volumes, and so on. Communication between the device and the logical target device. Therefore, in order to achieve the above purpose, the present invention provides a method for accessing a logical device using the 13 (: 31 protocol, so that the i SCS I protocol can not only provide SCSI physical devices, but also Logical devices such as RAID and logical volumes are provided to users, so users can directly enjoy the convenience and performance improvement brought by the server, instead of Multi increased hardware device present on the machine. Thereby

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[Implementation] Administrators of data systems and storage devices are often troubled by the need for data storage, and many people start to consider solutions. Virtual storage, a large number of different physical

The purpose of the preparation process is to help companies expand, centralize = large: knife storage devices. The invention uses the iscsi protocol not only for communication between physical devices, but also for communication of logical devices such as logical volumes and Raids. SCS I allows us to use Ethernet to build J p storage area networks. Through this method, 1 SCS I overcomes the limitation of directly connected storage, allowing us to share storage resources across different servers and servers, and expand storage capacity without stopping. The iSCSI system sends a SCSI command from a SCSH «(mostly implemented as a virtual SCSI card). The command is encapsulated in an information packet and sent. The receiver extracts the scs 丨 instruction from the packet and executes it, then encapsulates the returned SCS I response and data into the IP packet and sends them back to the sender. The system extracts data or instructions and passes them back to the s c s I subsystem. The S C S I C D B of the present invention is not passed to the S C S I subsystem for processing, but the SCSI CDB is unlocked in the module and then processed in the module according to the SCSI instruction.

Page 8 1231671 V. Description of the invention (5). Please refer to "Figure 2", which is a general flowchart of a method for accessing a logical device using the i SCS I protocol of the present invention. As shown in the figure, each target device file is first given a set of ID and logical unit number (step 2 1 0), and the access request of the initiator device is received. At the same time, the connection between the initiator device and the target device is established (step 2 2 0). ), Extract a SCSI protocol data unit from the connection (step 230), extract a SCSI command data block from the protocol data unit (step 240), and determine that the ID in the command data block corresponds to the logical unit number Device file, according to the SCS I instruction in the command data block, process the device file accordingly and create a corresponding response (step 250), construct the response into a SCSI protocol data unit, and send it back in the connection. To the initiating device (step 26). The invention enables the iSCSI protocol to use device files as physical hard disks under Linux. Please refer to "Figure 3" and Figure 5 is a flowchart of initialization of the present invention. When loading the modu 1 e, each device file is first opened (step 3 0 1), and each device file is given a set of ID and logical unit number (LUN) (step, step 3 02) ), On the same day, start the daemon one (responsible for processing connection creation) (step 303) and daemon three (interpret and handle SCSI CDB) (step 304), and then wait for the access of the boot device. ^ A "daemon process" (that is, a daemon process) is usually a background process, and it does not belong to any terminal shutdown, i. 1 'terminal session. Many system services are implemented by daemons, such as web services, printing, etc.

Page 91231671 V. Description of the invention (6) When the initiating device accesses, the 'daemon process accepts sockets from the initiating device from the kernel (the parameters from the initiating device are also included), and then the daemon establishes a connection and socket Word (S〇cket) · ^ in connection

In (Connection), daemon four (returns the SCSI PDU to the initiating device) and daemon two (processing the iSCSI PDU from the initiating device) are created in turn, and the connection established is transferred to daemon four and daemon process two. This process is repeated every time there is a new visit. Then the daemon process 2 extracts the header ’of i s c s I p D U from the connection, and then performs corresponding processing according to the instructions in the header. There are two types of commands: the first is I 〇 for SCSI hard disks or the request for scs I hard disk status; the second is other requests, such as requests for the status of "scs 丨 target device" ^ (target) , Parameter exchange, login, etc. If it is the first instruction, the SCSI CDB is extracted and then handed over to the daemon process three; if it is another request, then different responses will be made according to different instructions. See "Figure 4", daemon 3 extracts SCSI instructions from the connected SCSI CDB (step 4100), determines which LUN instruction (step 4 2 0 0) 'and discerns which instruction (step 4) 3 〇〇),

SCSI instructions include INQUIRY, READ, READ CAPACITY, and WRITE. If it is INQUIRY (step 4310), the type of response should be set to disk (step 4311), and the corresponding response is created (step X step response contains the type of device, manufacturer data, product data; ^ ^ read (step 43 2 0), calling the device file search and read functions ^ to (step 4321) 'The corresponding response was created; even

^ READ CAPACITY (step 43 3 0), the capacity of the device is calculated by 笪 山 Α / 卜 ττ (step

1231671 V. Description of the invention (7) 43 3 1), the corresponding response is created; if it is wRiTE (step 4340), the device file search and write function is called to write Data (20 9), and the corresponding response is Manufactured (210); if other instructions

Such as MODE SENSE, REPORT LUNS, START STOP UNIT, TEST UNIT READY, VERIFY, etc., the corresponding response is made by 4. The response is then made into an iSCSI PDU (step 4400). If there is DATA, the response and DATA are made into an iSCSI PDU, and then put back into the connection and waiting to be transmitted (step 4500). Whenever there is a new $ c s I instruction ’, this process will loop. In addition, whenever there is a new iSCSI PDU, the daemon IV will pass the iSCSI PDU from the connection back to the initiator. If you need to uninstall modu 1 e, all resources are cleared and each daemon is shut down. By applying the method for accessing a logical device using the i SCS I protocol of the present invention, a Raid, a logical volume (iogicai volume), etc. can be provided to a user for use. The method for implementing a logical volume under the i SCS I protocol in a disk array system is described below As an example, the present invention will be described in detail. Like disks, logical volumes can hold file systems, raw data areas, dump areas, or swap areas. Unlike diskettes, when you create a logical volume and then expand its size, the logical volume can choose a size. You can also expand logical volumes with multiple disks.

First, in the initialization phase, open the device file of the logical volume, assign a set of jD and LUN to this device file, and create a SCSI CDB processing daemon and a connection daemon. Please refer to "Figure 5", which is a flowchart of processing a SCSI CDB in a logical volume implementation method according to an embodiment of the present invention. When there is iSCSI PDU

1231671 hours V. Description of the invention (8) Object ^ 顿 51〇〇) 'Extract SCSI commands (step 5 2 0 0), identify the two types of command machine a (step 5 3 0 0). If it is INQUIRY (step 531 0), the type of the wild bird should be disk (step 5311), and the corresponding reply + factory step 531 2) is made, and the manufacturer data and product data are set. If it is READ step 53 2 〇), then the search and read functions of the logical volume are called to get Data. = Step 5 3 2 1) and create a corresponding response. If it is rEAD CAPACITY (step, 3⑼) ’, calculate the capacity of this logical volume (step 5 3 3 1) and make a response. If it is WRITE (step 5 3 40), the search and write function of the logical volume is called to write the data (step 5341) and a corresponding response is created.

Right ", other instructions (step 5350 0), such as MODE SENSE, REPORT 々LUNS, START STOP UNIT, TEST UNIT READY, VERIFY, etc., then create corresponding responses (step 5312). Subsequently, the iscsi PDU is generated including the response and the data (step 5400), and the iSCSI PD is then returned to the connection and waiting for transmission (step 5500). Although the present invention has been previously < > BU 乂 土 杳 _ 太 么 / |. 丄 IV ^ ^ ^ The preferred embodiment described above is disclosed above, but it is not intended to limit the present invention, so the spirit of Y Cheng and Within the scope, when it is known that this artist, 'without departing from the scope of the present invention

Page 121231671 The diagram briefly illustrates the implementation process of the iSCSI protocol. Figure 2 is a general flowchart of the method for accessing logical devices using the i SCS I protocol of the present invention. Figure 3 is the flowchart of the initialization of the present invention. FIG. 4 is a flowchart of processing the SCSI CDB according to the present invention; and FIG. 5 is a flowchart of a method for implementing a logical volume under the I SCS I agreement according to the embodiment of the present invention. [Illustration of Symbols]

110 Initiating device 120 Target device 121 Network subsystem 122 iSCSI module 123 SCSI subsystem

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Claims (1)

1231671 VI. Scope of patent application 1. A method for accessing a logical device by using the i SCS I agreement, which can realize the 'responsibility' transmission from the initiator to the logical target device, including the following steps: A set of ID and logical unit number (LUN) of the target device file; receiving the access request of the initiator device, and simultaneously establishing a connection (Connection) between the initiator device (Target) or the target device (Target); from the connection Extract scsi protocol data unit (PDU); Extract SCSI command data block (CDB) from the protocol data unit; determine the device file corresponding to the ID and logical unit number in the command data block, and according to the command data block The SCS I instruction processes the device file accordingly and creates a corresponding response; and constructs the response as a SCSI protocol data element into the connection and sends it back to the originating device. 2. The method for accessing a logical device using the i SCS 丨 protocol as described in item 1 of the scope of the patent application, which further includes receiving a socket from the initiating device (Socket) from the kernel and placing the socket in the Steps to connect ^. 3. The method for accessing a logical device using the i SCS I agreement as described in item 1 of the scope of patent application, wherein the logical target device is a logical volume 0 4. Use as described in item 1 of the scope of patent application i scs agrees on a method for accessing a logical device, wherein the logical target device is a redundant array of disks (Raid). Page 14 1231671 VI. Scope of patent application 5. The method for accessing a logical device using the i SCS I agreement as described in item 1 of the scope of patent application, wherein the SCSI instructions include INQUIRY, READ, READ CAPACITY, and WRITE. 6. The method for accessing a logical device using the i SCS I protocol as described in item 5 of the scope of the patent application, wherein if the SCSI instruction is INQUIRY, the type of the response is set to D i s k. 7. The method for accessing a logical device using the i SCS I agreement as described in item 5 of the scope of the patent application, wherein if the SCSI instruction is READ, the function of the device file is called to obtain D a t a. 8. The method for accessing a logical device using the i SCS I agreement as described in item 5 of the scope of patent application, wherein if the SCSI instruction is READ CAPACITY, the capacity of the device is calculated. 9. The method for accessing a logical device using the i SCS I agreement as described in item 5 of the scope of the patent application, wherein if the SCSI instruction is WRITE (10), the device file search and write functions are called to write Da t a. 10. The method for accessing a logical device using the i SCS I protocol as described in item 5 of the scope of the patent application, wherein the step of constructing the response into an SCS I agreement data unit is to construct the response and the Date into a SCSI agreement Data unit 0 3? 4 page 15