154Administering dynamic multipathing (DMP)

Administering DMP using vxdmpadm

The disable operation fails if it is issued to a controller that is connected to the root disk through a single path, and there are no root disk mirrors configured on alternate paths. If such mirrors exist, the command succeeds.

Enabling I/O for paths, controllers or array ports

Note: This operation is not supported for controllers that are used to access disk arrays on which cluster-shareable disk groups are configured.

Enabling a controller allows a previously disabled path, HBA controller or array port to accept I/O again. This operation succeeds only if the path, controller or array port is accessible to the host, and I/O can be performed on it. When connecting Active/Passive disk arrays, the enable operation results in failback of I/O to the primary path. The enable operation can also be used to allow I/O to the controllers on a system board that was previously detached.

To enable I/O for a path, use the following command:

#vxdmpadm enable path=path_name

To enable I/O for the paths connected to an HBA controller, use the following command:

#vxdmpadm enable ctlr=ctlr_name

To enable I/O for the paths connected to an array port, use one of the following commands:

#vxdmpadm enable enclosure=enclr_name portid=array_port_ID

#vxdmpadm [-f] disable pwwn=array_port_WWN

where the array port is specified either by the enclosure name and the array port ID, or by the array port’s worldwide name (WWN) identifier.

The following are examples of using the command to enable I/O on an array port:

#vxdmpadm enable enclosure=HDS9500V0 portid=1A

#vxdmpadm enable pwwn=20:00:00:E0:8B:06:5F:19

Upgrading disk controller firmware

You can upgrade disk controller firmware without performing a system reboot or unloading the VxVM drivers.

First obtain the appropriate firmware upgrades from your disk drive vendor. You can usually download the appropriate files and documentation from the vendor’s support website.