While doing some 5.0MP1 upgrades recently, I noticed that MPIO no longer controlled my vscsi root disks, coming from a Virtual I/O server. This was definitely not what I wanted. After a few calls and a few hours on the phone, I was finally told that MP1 finally had support for vscsi devices within Veritas, hence DMP taking control for multi-pathing. Due to the way I use vscsi devices for root disks, we had to disable this support. vscsi disks will still work through Veritas, they just use the standard ‘aixdisk’ format, rather than vscsi. To disable vscsi support I had to run the following
‘/usr/lib/vxvm/bin/vxdmpvscsi disable’, then reboot

Once the LPAR boot back up, everything was good to go. Existing volumes using vscsi devices continued to function.

The good: You can disable it
The bad: There’s no way to disable it before applying MP1… ugh.

This entry was posted on Friday, June 20th, 2008 and is filed under AIX 5.3. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.