ctlvsd Command

Purpose

Sets the operational parameters for the virtual shared disk subsystem on a node.

Syntax

ctlvsd
[-r node_number… | -R | -p parallelism |
 
-k node_number… | -t | -T | -v vsd_name ... |
 
-V | -C | -K | -M IP_max_message_size]

Description

The ctlvsd command changes some parameters of the virtual shared disk subsystem. When called with no arguments, the command displays the current and maximum cache buffer count, the request block count, the pbuf count, the minimum buddy buffer size, the maximum buddy buffer size, and the overall size of the buddy buffer.

Sequence number information may or may not be displayed. In general, sequence numbers and the options that reset them are managed entirely within the virtual shared disk and recoverable virtual shared disk subsystems.

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

vsd_name
Specifies a defined virtual shared disk.

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, see RSCT Administration Guide .

Examples

  1. To display the current parameters, enter: 
    ctlvsd
    The system displays a message similar to the following: 
    The minimum buddy buffer size is 4096.
The maximum buddy buffer size is 65536.
The total buddy buffer size is 4 max buffers, 262144 bytes.
  2. To display the current IP routing table, enter: 
    ctlvsd -t
    The system displays the following information: 
    Route cache information:
 
 destination  interface  ref  status  direct/gateway   min managed mbuf
     1           ml0      2     Up        Direct             256

Location

/opt/rsct/vsd/bin/ctlvsd