MPIO-capable device management

The Multiple Path I/O (MPIO) feature can be used to define alternate paths to a device for failover purposes.

Failover is a path-management algorithm that improves the reliability and availability of a device because the system automatically detects when one I/O path fails and re-routes I/O through an alternate path. All SCSI SCSD disk drives are automatically configured as MPIO devices and a select number of Fibre Channel disk drives can be configured as MPIO Other disk. Other devices can be supported, providing the device driver is compatible with the MPIO implementation in AIX®.

MPIO is installed and configured as part of BOS installation. No further configuration is required, but you can add, remove, re-configure, enable, and disable devices (or device paths) using SMIT, or the command-line interface. The following commands help manage MPIO paths:

mkpath: Adds a path to a target device.
rmpath: Removes a path to a target device.
chpath: Changes an attribute or the operational status of a path to a target device.
lsmpio: Displays information such as the status, configuration, and statistics about multiPath I/O (MPIO) storage devices.
lspath: Displays information about paths to a target device.

If you are performing a BOS installation or a mksysb installation on a disk with multiple ports such as Multipath I/O (MPIO), the port must remain active for the duration of the install.