Defrag your SAN?

Lanz · 2 Mar 2010 at 00:05

Do you defrag your SAN?

I've never bothered, mainly because my old manager said it wasnt needed. Now he's gone and I'm in charge, Im wondering if I should bother?

zetec452 · 2 Mar 2010 at 00:19

It depends on what is on the SAN, what file system it uses and what software you are defragging? I guess you have your SAN connected to an MS machine?

Lanz · 2 Mar 2010 at 08:04

Like a windows fileserver, user data, roaming profiles etc.

RSR · 2 Mar 2010 at 09:09

It depends on the SAN tech being used. NetApp filers use a WAFL layout, so there is no need to defrag them.

bluebox · 2 Mar 2010 at 13:52

It's a good way of making senior management think you need new storage. Just run a defrag and watch the performance drop

On a serious note the majority of disk controllers won't have much of a problem with this. Fragmentation hits performance on a single disk in a PC a lot more than it would across multiple spindles in an array on a SAN and has already been said some disk controllers just don't have the problem.

Vanilla · 2 Mar 2010 at 19:36

andyd said:
It depends on the SAN tech being used. NetApp filers use a WAFL layout, so there is no need to defrag them.

Yes you do! There's a tool for it called WAFL IRON and you'll need it depending on your snap usage.

SMN · 2 Mar 2010 at 20:29

All depends on the file system. Generally fragmentation raises seek time significantly so it is advisable but depends on vendor and proprietary FS's.

RSR · 2 Mar 2010 at 21:51

Interesting Link.

http://www.las-solanas.com/storage_virtualization/san_volume_defragmentation.php

RSR · 2 Mar 2010 at 21:57

Vanilla said:
Yes you do! There's a tool for it called WAFL IRON and you'll need it depending on your snap usage.

Ive been told that its not worth doing on NetApp's due to the WAFL and they way it records locations in meta data.

Ill have a look on the NetApp now site now.

Edit: Ive had a look on the Now, I stand correct. However, ive also noticed a lot of errors due to wafl_iron.

http://www.storagemonkeys.com/index...ewdiscussion&groupid=45&topicid=33&Itemid=138