Setting Up Multipathing

If you choose to use it, set up multipathing before you install SAP ASE.

On AIX, multiple path I/O (MPIO) is installed and configured as part of the IBM base operating system (BOS) installation. No further configuration is required, but you can add, remove, reconfigure, enable, and disable devices (or device paths) using SMIT, Web-based System Manager, or the command line interface.

By default, MPIO is enabled on all disks and LUNs (logical unit numbers) that have this capability, which prevents third-party multipathing drivers (such as Veritas DMP or EMC PowerPath) from managing the paths to such devices. To allow a third-party multipathing driver to manage multipathing instead of MPIO, install suitable object data manager (ODM) definitions for the devices on the host.

To configure multiple paths for all LUNs, add all of the adapters and fibre-channel cables and run the cfgmgr command. You might have to run cfgmgr multiple times. See the IBM System Storage Multipath Subsystem Device Driver User's Guide for details about using the cfgmgr command.

The /dev/rhdiskN devices are persistent; use these device names to access the multipathed devices.

These commands help manage MPIO paths:

lspath – displays multipath device configuration.
mkpath – adds a path for a multipath device.
chpath – configures multipath device.
rmpath – removes a path for a multipath device.
lsattr – displays device configuration.
lsdev – displays system devices.
mkdev – creates and enables system devices.
chdev – configures system devices.
rmdev – removes and disables system devices.