Commands Reference, Volume 1

chpath Command

Purpose

Changes the operational status of paths to a multipath I/O (MPIO) capable device.

Syntax

chpath -l Name -s OpStatus [ -D ] [ -p Parent ] [ -w Connection ] [ -v Level ]

chpath -h

The chpath command changes the operational status of paths to the specified device (the -l Name flag). The set of paths to change is obtained by taking the set of paths from the Customized Paths (CuPath) object class for the specified device whose Path_Status descriptor is set to Path_Available and qualifying these paths based on matching the objects' Parent and Connection descriptors against any -p Parent and -w Connection flags specified. If neither the -p nor the -w flag is specified, the set of paths changed consists of all the device's paths in the CuPath object class that are configured.

The operational status of a path refers to the usage of the path as part of MPIO path selection. The value of enable indicates that the path is to be used while disable indicates that the path is not to be used. disable impacts future I/O, not I/O already in progress. As such, a path can be disabled, but still have outstanding I/O until such time that all of the I/O that was already in progress completes. If -s disable is specified for a path and I/O is outstanding on the path, this is indicated in the command's output. When the chpath command finishes, it displays the results for each path impacted by this command.

Note: This command changes the operational status of the paths in the system; the path_status descriptor in the corresponding CuPath objects is not changed. It is possible for this command to change the operational status for some paths and not for others.

Flags

-D	Indicates that it is acceptable to disable the last path to a device. This flag is only valid with the -s disable flag. Without this flag, the chpath command fails if the requested change would result in all paths to the device being disabled.
-h	Displays the command usage message.
-l Name	Specifies the logical device name of the device whose path status is to be changed. The paths to be changed are qualified through the -p and -w flags.
-p Parent	Indicates the logical device name of the parent device to use in qualifying the paths to be changed.
-s OpStatus	Indicates the operational status to which the indicated paths should be changed. The allowable values for these flags are as follows: *enable* Marks the operational status as enabled for MPIO selection. *disable* Marks the operational status as disabled for MPIO path selection. This command fails if the result would disable all available paths and the -D flag is not specified.
-v Level	Indicates that verbose output at the indicated Level is desired. The only allowable value for this flag is debug. This provides information for diagnosing command problems.
-w Connection	Indicates the connection information to use in qualifying the paths to be changed.

Examples

To disable the paths between scsi0 and hdisk1 disk device, type:
```
chpath -l hdisk1 -p scsi0 -s disable
```
The system displays a message similar to one of the following (where the second variant indicates that there is outstanding I/O for the path):
```
disk1 path from parent scsi0 connection 5,0 disabled
```
or
```
disk1 path from parent scsi0 connection 5,0 disabling
```

To enable all paths to hdisk1 disk device, type:

chpath -l hdisk1 -s enable

The system displays a message similar to the following:

hdisk1 path from parent scsi0 connection 5,0 enabled

hdisk1 path from parent scsi1 connection 5,0 enabled

Files

/usr/sbin/chpath

Contains the chpath command.