AIX, VIO, MPIO, and Powerpath

Maybe another way how it could work for you:
Create two storage groups, each for every VIO.
Add the luns you would like to share to both storage groups.
Be sure that the HOST IDs for the luns are the same in both groups.

Where do you use MPIO? (you wrote you use powerpath on both VIOs...)

I don't understand why you would want to do this.

One host accessing one lun from one storage system, but through two VIO servers.

The only thing you are protecting against is HBA failure.

I also technically don't see how this would work, cause the AIX LVM (on the VIO) will write the vgid/lvid(s) onto there as well. So unless you first set the LUN up on one VIO, then import it on the other, still I don't see how thats going to work.

Honestly mate, I don't think this is what it was designed for, can't you just do something like two LUNs, one to each VIO, present them to your host then mirror them via the LVM? You would essentially get the same result and it will work.

Cheers.

I went through this process ~12 months back with a p570 (AIX 5.3) and a CX700 (v19). Two useful EMC docs are solution "emc109158" and "Virtual I/O Server - Technical Note - P/N 302-002-143". These should be available from Powerlink.

From memory (and at the risk of stating the obvious) other things to check are:
- AIX is at the correct level & has the latest APARs applied to both the VIO & client lpars.
- The HBAs assigned to the VIOs have been updated with the latest firmware.
- The latest ODM drivers have been loaded on the VIOs. Note that disks assigned to the VIOs must display as CLARiiON/EMC not generic SCSI.
- The correct or latest version of PowerPath has been loaded on the VIO lpars. Note the client lpars use MPIO not PPath.

You are also protecting against VIO-server failure. You can shutdown a single VIO-server whenever you want without shutting down VIO-clients first. Very important feature with production VIO-clients.

Of course you have to pass the whole disk (hdiskpower) to VIO-client without LVM intevention at the VIO-server.

We do this in our environment (although with DMX not CLARiiON... but we have tested with CLARiiON). There are very good reasons for doing this.

As previously mentioned this configuration protects against VIO failure, but even beyond that it insulates the partitions behind the VIO LPARs from planned VIO outages for things like patching and upgrades. Take down one VIO and do maintenance on it then bring it up an update the second one. No storage outage to the micro partitions behind them.

As for the earlier question about how MPIO is getting used, I can tell you haw we use it in our situation. We put PowerPath on the VIO LPARs to ensure full active/active redundancy and load balancing, then use MPIO on the micro partitions to manage the multiple paths (through the two VIO LPARs).