Re: Mixing FastT hdisks and ESS vpaths

I agree with simon. As a business partner, one of our major functions is data migration, and this is the preferred method.

I assume the business partner is recommending that the RDAC controlled (FAStT) disk will be presented over a seperate set of HBAs(RDAC/SDD have conflicts).

Another option for online migration with minimal service outtage involves the implementation of SAN Volume Controllers; creating SVC image-mode disks of the ESS disk, and then migrating them to SVC controlled FAStT vdisks. This doesnt require a seperate set of HBAs(SVC uses SDD), and requires only a minimal outtage to convert the ESS disk to SVC image-mode disks. This method has been extremely successful for me, and is considerably less work than using mklvcopy/migratepv








-----Original Message-----
From: IBM AIX Discussion List on behalf of Green, Simon
Sent: Tue 12/5/2006 5:19 AM
To: aix-l@xxxxxxxxxxxxx
Subject: Re: Mixing FastT hdisks and ESS vpaths

I've never heard of such a thing and it seems very unlikely. LVM
doesn't care what sort of disks they are - that's half the point of
having it in the first place: so you deal with Logical not Physical
storage. One could probably make a case that it's not a great idea from
a long-term storage management perspective, but I can't see anything
wrong with it as a transitory solution.

--
Simon Green

-----Original Message-----
From: IBM AIX Discussion List [mailto:aix-l@xxxxxxxxxxxxx] On Behalf Of
AIX Geek
Sent: 04 December 2006 23:05
To: aix-l@xxxxxxxxxxxxx
Subject: Mixing FastT hdisks and ESS vpaths


Can anyone point me to some documentation that says that FastT hdisks
and ESS vpaths should *NOT* be mixed in a volume group?

Planning a migration (from Shark onto FastT) and the proposal on the
table from a business partner is to add the FastT hdisks to the VG and
mirror. Conceptually, it's OK. But other sources have called out the
fact that IBM doesn't support FastT hdisks and ESS vpaths in the same
volume group.

True, false, or true-with-caveats?

Relevant Pages

  • Re: Mixing FastT hdisks and ESS vpaths
    ... you can have both on a system as long as you use separate pairs of HBA's for each storage device. ... Mixing FastT hdisks and ESS vpaths ...
    (AIX-L)
  • Re: Mixing FastT hdisks and ESS vpaths
    ... doesn't care what sort of disks they are - that's half the point of ... a long-term storage management perspective, ... Can anyone point me to some documentation that says that FastT hdisks ... and ESS vpaths should *NOT* be mixed in a volume group? ...
    (AIX-L)