defvsd Command

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Purpose

Designates a node as either having or using a virtual shared disk.

Syntax

defvsd logical_volume_name global_group_name vsd_name

Description

This command is run to specify logical volumes residing on globally accessible volume groups to be used as virtual shared disks.

You can use the System Management Interface Tool (SMIT) to run the defvsd command. To use SMIT, enter:

smit vsd_data

and select the Define a Virtual Shared Disk option.

Flags

-r
Resets the outgoing and expected sequence numbers for the nodes specified on the node on which the command is run. Use this flag when another node has either been rebooted, cast out, or all virtual shared disks have been reconfigured on that node. The specified nodes are also cast in.
Note: This option should be used only under direct guidance from IBM® Service. It should never be used under normal circumstances.
-R
Resets the outgoing and expected sequence number for all nodes on the node on which the command is run. Use this flag after rebooting the node. All nodes in the virtual shared disk network will be cast in.
Note: This option should be used only under direct guidance from IBM Service. It should never be used under normal circumstances.
-p
Sets the level of virtual shared disk parallelism to the number specified. The valid range is 1 to 9. The default is 9. A larger value can potentially give better response time to large requests. (See RSCT for AIX 5L: Managing Shared Disks for more information regarding tuning virtual shared disk performance.)

This value is the buf_cnt parameter on the uphysio call that the virtual shared disk IP device driver makes in the kernel. Use statvsd to display the current value on the node on which the command is run.

-k
Casts out the node numbers specified on the local node. The local node ignores requests from cast out nodes. Use -r to cast nodes back in.
Note:
  1. Before using this flag, refer to the “Restrictions” section that follows.
  2. This option should be used only under direct guidance from IBM Service. It should never be used under normal circumstances.
-t
Lists the current routing table and mbuf headers cached by the virtual shared disk driver.
-T
Clears or releases all cached routes.
-v vsd_name ...
Resets the statistics in the number of read and write requests on the specified virtual shared disks.
-V
Resets all the configured virtual shared disk's statistics in the number of read and write requests.
-C
Resets the virtual shared disk device driver counters displayed by the statvsd command. Exceptions are the outgoing and expected request sequence numbers among the client and server nodes.
-K
Casts out all nodes on the local node. Local requests are still honored.
Note:
  1. Before using this flag, refer to the “Restrictions” section that follows.
  2. This option should be used only under direct guidance from IBM Service. It should never be used under normal circumstances.
-M
Sets the virtual shared disk maximum IP message size. This is the largest sized block of data the virtual shared disk sends over the network for an I/O request. This limit also affects local virtual shared disk I/O block size. The value is in bytes and must not be greater than the maximum transmission unit (MTU) size of the network. All nodes should use the same value. The recommended values are:
  • 61440 (60KB) for a switch
  • 8192 (8KB) for jumbo frame Ethernet
  • 1024 (1KB) for 1500-byte MTU Ethernet

Parameters

logical_volume_name
Is the name of the logical volume you want to specify as a virtual shared disk. This logical volume must reside on the global volume group indicated. The length of the name must be less than or equal to 15 characters.
global_group_name
Is the name of the globally-accessible volume group previously defined by the vsdvg command where you want to specify a virtual shared disk. The length of the name must be less than or equal to 31 characters.
vsd_name
Specifies a unique name for the new virtual shared disk. This name must be unique within the RSCT peer domain, and, in order to avoid possible future naming conflicts, should also be unique across the overall cluster. The suggested naming convention is vsdnngvg_name. The length of the name must be less than or equal to 31 characters.
Note: If you specify a vsd_name that is already the name of another device, the cfgvsd command will be unsuccessful for that virtual shared disk. This error ensures that the special device files created for the name do not overlay and destroy files of the same name representing some other device type (such as a logical volume).

Security

You must have root authority to run this command.

Restrictions

You must issue this command from a node that is online in the peer domain. To bring a peer domain online, use the startrpdomain command. To bring a particular node online in an existing peer domain, use the startrpnode command. For more information on creating and administering an RSCT peer domain, refer to RSCT Administration Guide .

Examples

  1. The following example specifies that, on the globally accessible volume group vg1n1, the logical volume known as lv1vg1n1 is used as a virtual shared disk named vsd1vg1n1. 
    defvsd lv1vg1n1 vg1n1 vsd1vg1n1

Location

/opt/rsct/vsd/bin/defvsd