It really depends on your situation. FlexVols on small systems can be really useful, especially if you need multiple volumes or have small data sets. The ability to allow small volumes to be striped across lots of disks could easily outweigh any memory cache performnace issues.

I'm not saying Blake's necessarily wrong here, it's just that like most interesting questions, the answer is usually "It depends". In this case it depends on the layout, structure, and usage of the data.

-- Adam Fox adamfox@netapp.com

-----Original Message----- From: Blake Golliher [mailto:thelastman@gmail.com] Sent: Monday, June 05, 2006 8:17 PM To: Fox, Adam; Michael Homa Cc: toasters@mathworks.com Subject: Re: Suggestions regarding migration from 740 to 270

It's probably not the best idea to go to flexvols on such a small memory system. Flexvols need use more memory just by it's nature, and will eat away at your read cache on the 270 (which is already small). Maybe just to trad vols, and snapmirror? Or if you really needed the features in flexvols? In that case, this is just an FYI.

-Blake

On 6/5/06, Fox, Adam Adam.Fox@netapp.com wrote:

It is possible to preserve snapshots and migrate data, but it's tedious at best and unpractical at worst, it just depends on your data.

You can use ndmpcopy or qtree SnapMirror (I prefer QSM if you have

it).

But basically you start with the oldest snapshot you want to keep. Migrate that snapshot for each qtree you want to migrate (or I suppose you can just

do the volume if you are doing ndmpcopy). Then take a local snapshot on the destination flex vol (probably with the same name).

Repeat this process with each snapshot you want to preserve. Basically, you are building them from the ground up. It works, but like I said, it's tedious for most and impossible for some.

Another alternative for those who don't want to go through this process is to just copy the active filesystem over using anything you want, then keep the older disks around until they would have been deleted anyway. Not sure how that would work with your manual snapshots, but some sites with time-based snapshots have found that to

be more practical, even if a bit inconvient, for a few weeks/months.

Hope this helps.

-- Adam Fox adamfox@netapp.com

-----Original Message----- From: Michael Homa [mailto:mhoma@uic.edu] Sent: Monday, June 05, 2006 3:51 PM To: toasters@mathworks.com Subject: Suggestions regarding migration from 740 to 270

Hi:

Recently, we elected to replace our primary 740 (we have two) with a 270. The 740, running 6.4.5, has traditional volumes whereas the 270, running 7.0.4, has flex volumes. I'm using ndmpcopy to migrate volumes

from the old box to the new. My question concerns snapshots. I was told that I can't use ndmpcopy to migrate the snapshot (if that's not true, feel free to tell me). Anyway, we have some user-created snapshots that hold important changes. I'm looking for suggestions on getting the information contained in the snapshots migrated.

Thanks

Michael Homa Operating Systems Support and Database Group Academic Computing and Communication Center University of Illinois at Chicago email: mhoma@uic.edu