Ack, I was seconds away from writing the same post as Nick Triantos on Upgrading from non-ALUA to ALUA, as I’ve spent the afternoon so far doing this and documenting the process.
The process works great, and it didn’t disrupt my clusters at all. The only things I did differently were:
1. I issued the “/usr/sbin/esxcli nmp satp setdefaultpsp –psp VMW_PSP_RR –satp VMW_SATP_ALUA” command on all the hosts prior to rebooting them.
2. I was able to combine this work with the application of the ESX 4.0 patch for the RAID controller cache problems, so Update Manager took care of all the rebooting for me. It does feel good to be lazy some days.
If you have a NetApp array and are running ESX 4.0 I wholeheartedly suggest enabling ALUA. As Vaughn Stewart puts it, it really is Plug & Play, and it removes all the manual tuning & balancing you needed to do to spread I/O across all your HBAs while making sure you’re talking directly to the right storage controllers.
As an EMCer, I agree – ALUA rocks!
Yeah — I’m spoiled, though, as my only exposure to EMC gear currently is a DMX-3. No need for ALUA there…