Patent Application
20170168739
This patent application claims priority to Indian Patent Application Number 6638/CHE/2015, filed Dec. 11, 2015, and entitled “ACCESSING A VIRTUAL VOLUME ON A STORAGE ARRAY,” which is incorporated herein by reference in its entirety.
Computer data is vital to today's organizations and a significant part of protection against disasters is focused on data protection. Conventional data protection systems include tape backup drives, for storing organizational production site data on a periodic basis. Another conventional data protection system uses data replication, by creating a copy of production site data of an organization on a secondary backup storage system, and updating the backup with changes. The backup storage system may be situated in the same physical location as the production storage system, or in a physically remote location. Data replication systems generally operate either at the application level, at the file system level, or at the data block level.
In one aspect, a method includes receiving, at a storage array, a command to a virtual volume from a host, extracting a virtual volume index from the command; reading a table using the virtual volume index to determine the logical unit where the virtual volume is stored and executing the command at the logical unit with the virtual volume. The command is one of a read command to read data from the virtual volume or a write command to write data to the virtual volume.
In another aspect, an apparatus includes electronic hardware circuitry configured to receive, at a storage array, a command to a virtual volume from a host, extract a virtual volume index from the command, read a table using the virtual volume index to determine the logical unit where the virtual volume is stored and execute the command at the logical unit with the virtual volume. The command is one of a read command to read data from the virtual volume or a write command to write data to the virtual volume.
In a further aspect, an article includes a non-transitory computer-readable medium that stores computer-executable instructions. The instructions cause a machine to receive, at a storage array, a command to a virtual volume from a host, extract a virtual volume index from the command, read a table using the virtual volume index to determine the logical unit where the virtual volume is stored and execute the command at the logical unit with the virtual volume. The command is one of a read command to read data from the virtual volume or a write command to write data to the virtual volume.
A version of virtual volumes (VVols) is no longer accessible by traditional hosts (e.g., hosts that are not VMWARE® ESX® of VMWARE® ESXi™ hosts). It is expensive to purchase additional special servers in order to communicate with VVols. There are a number of traditional hosts that need to test with virtual volumes with a significant amount of investment in test utilities designed to work on these traditional hosts. Described herein are techniques to access a virtual volume on a storage array using traditional hosts which will allow previous testing tools to be used without designing new tools. In one example, VVols include but are not limited to VMWARE® virtual volumes.
The following definitions may be useful in understanding the specification and claims.
HOST—at least one computer or networks of computers that runs at least one data processing application that issues I/O requests to one or more storage systems;
I/O REQUEST—an input/output request (sometimes referred to as an I/O), which may be a read I/O request (sometimes referred to as a read request or a read) or a write I/O request (sometimes referred to as a write request or a write);
LOGICAL UNIT—a logical entity provided by a storage system for accessing data on the storage system. The logical disk may be a physical logical unit or a virtual logical unit; and
LUN—a logical unit number for identifying a logical unit;
READ COMMAND—a read request to read data (a read I/O request); and
WRITE COMMAND—a write request to write data (a write I/O request).
Referring to
The storage array 104 includes a protocol endpoint (PE) 112, a table 116 and virtual volumes (VVol) 118a-118c. The VVol 118a data is stored on a LUN 1, VVol 118b data is stored on a LUN 2 and VVol 118c data is stored on a LUN 40. The table 116 is used to translate a virtual volume index to a LUN.
The PE 112 is a logical I/O proxy. That is, the PE 112 has an address (e.g., Fibre channel address) and to the host 102 looks like a logical unit but with no storage. When there is an association (e.g., a logical connection in the code) between a virtual volume and the PE 112, then the PE 112 may be used to communicate with the virtual volume.
Each test application 106a-106c configured to have its own storage device (i.e., the test application 106a has storage device 110a, the test application 106b has storage device 110b and the test application 106c has storage device 110c) when in reality these storage devices 110a-110c do not exist on the host 102 at all; but rather, the test application s 106a-106c are reading and writing to the storage array 104.
In one particular example, the multipath module 108 is configured to run a management command (e.g., a SCSI (Small Computer System Interface) command). In one example, the management command is configured to associate VVol 118a to the 112 PE. When executed on the storage array 104, the PE 112 will return a status message (e.g., a SCSI message) indicating the index associated with VVol 118a, which is stored in the table 111 (along with table 116).
Referring to
Process 200 embeds a virtual volume existence indicator (VVolEI) in the read or write command received (204). In one example, the multipath module 108 embeds a VVolEI into a read or write command (e.g., a SCSI command) to indicate that virtual volumes exists and are being read or written to. In another example, the VVolEI is used by the storage array (e.g., the protocol endpoint 112) to look for a VVol index in a particular location in the read or write command. In some examples, the VVolEI may be embedded in a reserved byte of the read or write command or in a control byte of the read or write command. In one particular example, the VVolEI is a first bit in a control byte.
Process 200 embeds a virtual volume index in the read or write command received (208). In one example, the multipath module 108 embeds a virtual volume index from the table 111 into the read or write command to indicate the logical unit where the virtual volume is being read or written to. In other examples, a filter driver residing below the SCSI driver communicates with the MPIO 108 to determine which VVol index to embed. In some examples, the VVol index may be embedded in a reserved byte of the read or write command or in a control byte of the read or write command. In one particular example, the virtual volume index uses bits 2-7 in a control byte of the read or write command.
Process 200 sends the altered read or write command to the storage array (210). For example, the multipath module 108 sends the altered read or write command to the storage array 104.
Referring to
Process 300 receives the altered read or write command (302). For example, the PE 112 receives the altered read or write command from the host 102.
Process 300 extracts the virtual volume existence indicator (306). For example, the PE 112 extracts the VVolEI from the read or write command. In one example, the VVolEI having a logical “1” value indicates that virtual volumes exists and are being read or written to while VVolEI having a logical “0” value indicates a virtual volume is not being used. In some examples, a VVolEI is not used at all.
Process 300 extracts the virtual volume index if the virtual volume existence indicator indicates a virtual volume exists (308). For example, if the PE 112 determines that a virtual volume exists then the PE 112 will read the location in the read or write command where the virtual volume index exists.
Process 300 reads a table to identify the LUN using the virtual volume index (310). For example, the PE 112 reads the table 116 and identifies the logical unit containing the virtual volume that will be read or written to according to the virtual volume index extracted from the altered read or write command.
Process 300 performs the read or write command on the logical unit identified in the table (312). For example, the PE 112 performs the read or write command on the virtual volume indicated in processing block 310.
Referring to
Referring to
The processes described herein (e.g., processes 200 and 300) are not limited to use with the hardware and software of
The system may be implemented, at least in part, via a computer program product, (e.g., in a non-transitory machine-readable storage medium such as, for example, a non-transitory computer-readable medium), for execution by, or to control the operation of, data processing apparatus (e.g., a programmable processor, a computer, or multiple computers)). Each such program may be implemented in a high level procedural or object-oriented programming language to communicate with a computer system. However, the programs may be implemented in assembly or machine language. The language may be a compiled or an interpreted language and it may be deployed in any form, including as a stand-alone program or as a module, component, subroutine, or other unit suitable for use in a computing environment. A computer program may be deployed to be executed on one computer or on multiple computers at one site or distributed across multiple sites and interconnected by a communication network. A computer program may be stored on a non-transitory machine-readable medium that is readable by a general or special purpose programmable computer for configuring and operating the computer when the non-transitory machine-readable medium is read by the computer to perform the processes described herein. For example, the processes described herein may also be implemented as a non-transitory machine-readable storage medium, configured with a computer program, where upon execution, instructions in the computer program cause the computer to operate in accordance with the processes. A non-transitory machine-readable medium may include but is not limited to a hard drive, compact disc, flash memory, non-volatile memory, volatile memory, magnetic diskette and so forth but does not include a transitory signal per se.
The processes described herein are not limited to the specific examples described. For example, the processes 200 and 300 are not limited to the specific processing order of
The processing blocks (for example, in the processes 200 and 300) associated with implementing the system may be performed by one or more programmable processors executing one or more computer programs to perform the functions of the system. All or part of the system may be implemented as, special purpose logic circuitry (e.g., an FPGA (field-programmable gate array) and/or an ASIC (application-specific integrated circuit)). All or part of the system may be implemented using electronic hardware circuitry that include electronic devices such as, for example, at least one of a processor, a memory, a programmable logic device or a logic gate.
Elements of different embodiments described herein may be combined to form other embodiments not specifically set forth above. Other embodiments not specifically described herein are also within the scope of the following claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 6638/CHE/2015 | Dec 2015 | IN | national |
