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Sun Cluster System Administration Guide for Solaris OS

Administering Disk-Path Monitoring

Disk path monitoring (DPM) administration commands enable you to receive notification of secondary disk-path failure. Use the procedures in this section to perform administrative tasks that are associated with monitoring disk paths. Refer to “Key Concepts for Administration and Application Development” in Sun Cluster Concepts Guide for Solaris OS for conceptual information about the disk-path monitoring daemon. Refer to the scdpm(1M) man page for a description of the scdpm command options and related commands. Refer to the syslogd(1M) man page for logged errors that are reported by the daemon.

Note –

Disk paths are automatically added to the monitoring list monitored when I/O devices are added to a node by using the scgdevs or scdidadm commands. Disk paths are also automatically unmonitored when devices are removed from a node by using Sun Cluster commands.

Table 4–5 Task Map: Administering Disk-Path Monitoring

Task 

For Instructions 

Monitor a disk path by using the scdpm command

How to Monitor a Disk Path

Unmonitor a disk path by using the scdpm command

How to Unmonitor a Disk Path

Print the status of faulted disk paths for a node by using scdpm

How to Print Faulted Disk Paths

Monitor or unmonitor disk paths from a file by using scdpm -f

How to Monitor Disk Paths From a File

The procedures in the following section issue the scdpm command with the disk-path argument. The disk-path argument is always constituted of a node name and a disk name. The node name is not required and defaults to all if none is specified. The following table describes the conventions that are used for naming the disk path.

Note –

Use of the global disk-path name is strongly recommended, because the global disk-path name is consistent throughout the cluster. The UNIX disk-path name is not consistent throughout the cluster. The UNIX disk path for one disk can differ from cluster node to cluster node. The disk path could be c1t0d0 on one node and c2t0d0 on another node. If you use UNIX disk-path names, use the scdidadm -L command to map the UNIX disk-path name to the global disk-path name before issuing DPM commands. See the scdidadm(1M) man page.

Table 4–6 Sample Disk-Path Names

Name Type 

Sample Disk-Path Name 

Description 

Global disk path  

phys-schost-1:/dev/did/dsk/d1

Disk path d1 on the phys-schost-1 node

all:d1

Disk path d1 on all nodes in the cluster

UNIX disk path  

phys-schost-1:/dev/rdsk/c0t0d0s0

Disk path c0t0d0s0 on the phys-schost-1 node

phys-schost-1:all

All disk paths on the phys-schost-1 node

All disk paths 

all:all

All disk paths on all nodes of the cluster 

How to Monitor a Disk Path

Perform this task to monitor disk paths in your cluster.

Caution – Caution –

DPM is not supported on nodes that run versions that were released prior to Sun Cluster 3.1 5/03 software. Do not use DPM commands while a rolling upgrade is in progress. After all nodes are upgraded, the nodes must be online to use DPM commands.

  1. Become superuser on any node in the cluster.

  2. Monitor a disk path by using the scdpm command. 


    # scdpm -m node:disk path

    Refer to Table 4–6 for naming conventions for the node:disk path argument.

  3. Verify that the disk path is monitored.


    # scdpm -p node:all

Example—Monitoring a Disk Path on a Single Node

The following example monitors the schost-1:/dev/did/rdsk/d1 disk path from a single node. Only the DPM daemon on the node schost-1 monitors the path to the disk /dev/did/dsk/d1.


# scdpm -m schost-1:d1
# scdpm -p schost-1:d1
	     schost-1:/dev/did/dsk/d1   Ok

Example—Monitoring a Disk Path on All Nodes

The following example monitors the schost-1:/dev/did/dsk/d1 disk path from all nodes. DPM starts on all nodes for which /dev/did/dsk/d1 is a valid path.


# scdpm -m all:/dev/did/dsk/d1
# scdpm -p schost-1:d1
	     schost-1:/dev/did/dsk/d1   Ok

Example—Rereading the Disk Configuration From the CCR

The following example forces the daemon to reread the disk configuration from the CCR and prints the monitored disk paths with status. 


# scdpm -m all:all 
# scdpm -p all:all
		 schost-1:/dev/did/dsk/d4   Ok
	     schost-1:/dev/did/dsk/d3   Ok
	     schost-2:/dev/did/dsk/d4   Fail
	     schost-2:/dev/did/dsk/d3   Ok
	     schost-2:/dev/did/dsk/d5   Unmonitored
	     schost-2:/dev/did/dsk/d6   Ok

How to Unmonitor a Disk Path

Use this procedure to unmonitor a disk path.

Caution – Caution –

DPM is not supported on nodes that run versions that were released prior to Sun Cluster 3.1 5/03 software. Do not use DPM commands while a rolling upgrade is in progress. After all nodes are upgraded, the nodes must be online to use DPM commands.

  1. Become superuser on any node in the cluster.

  2. Determine the state of the disk path to unmonitor.


    # scdpm -p [all:] disk path
    -p

    Prints a detailed listing of the current status of a specified disk path

    [:all]

    Displays all monitored and unmonitored disk paths

  3. On each node, unmonitor the appropriate disk paths.


    # scdpm -u  node:disk path

    Refer to Table 4–6 for naming conventions for the node:disk path argument.

Example—Unmonitoring a Disk Path

The following example unmonitors the schost-2:/dev/did/rdsk/d1 disk path and prints disk paths with status for the entire cluster.


# scdpm -u schost-2:/dev/did/rdsk/d1
# scdpm -p all:all 
	     schost-1:/dev/did/dsk/d4   Ok
	     schost-1:/dev/did/dsk/d3   Ok
	     schost-2:/dev/did/dsk/d4   Fail
	     schost-2:/dev/did/dsk/d3   Ok
	     schost-2:/dev/did/dsk/d1   Unmonitored
	     schost-2:/dev/did/dsk/d6   Ok

How to Print Faulted Disk Paths

Use the following procedure to print the faulted disk paths for a cluster.

Caution – Caution –

DPM is not supported on nodes that run versions that were released prior to Sun Cluster 3.1 5/03 software. Do not use DPM commands while a rolling upgrade is in progress. After all nodes are upgraded, the nodes must be online to use DPM commands.

  1. Become superuser on any node in the cluster.

  2. Print the faulted disk paths throughout the cluster.


    # scdpm -p -F node:disk path

    Refer to Table 4–6 for naming conventions for the node:disk path argument.

Example—Printing Faulted Disk Paths

The following example prints faulted disk paths for the entire cluster. 


# scdpm -p -F [all:]all
		 schost-1:/dev/did/dsk/d4   Fail
	     schost-1:/dev/did/dsk/d3   Fail
	     schost-2:/dev/did/dsk/d4   Fail
	     schost-2:/dev/did/dsk/d3   Fail
	     schost-2:/dev/did/dsk/d5   Fail
	     schost-2:/dev/did/dsk/d6   Fail

How to Monitor Disk Paths From a File

Use the following procedure to monitor or unmonitor disk paths from a file. The file must list the commands to monitor or unmonitor, the node names, and the disk-path names. Each field of the file should be separated by a column. Format each listing by following the example.


syntax in command file:
[u,m] [node|all]:<[/dev/did/rdsk/]d- | [/dev/rdsk/]c-t-d- | all>

command file entry
u schost-1:/dev/did/rdsk/d5
m schost-2:all

Caution – Caution –

DPM is not supported on nodes that run versions that were released prior to Sun Cluster 3.1 5/03 software. Do not use DPM commands while a rolling upgrade is in progress. After all nodes are upgraded, the nodes must be online to use DPM commands.

  1. Become superuser on any node in the cluster.

  2. Monitor the disk paths from a file.


    # scdpm -f filename

  3. Verify the disk paths with status for the cluster.


    # scdpm -p all:all

Example—Monitor or Unmonitor Disk Paths From a File

The following example monitors or unmonitors disk paths from a file. 


# scdpm -f schost_config
# scdpm -p all:all 
	     schost-1:/dev/did/dsk/d4   Ok
	     schost-1:/dev/did/dsk/d3   Ok
	     schost-2:/dev/did/dsk/d4   Fail
	     schost-2:/dev/did/dsk/d3   Ok
	     schost-2:/dev/did/dsk/d5   Unmonitored
	     schost-2:/dev/did/dsk/d6   Ok