RAID 5 stripe size and newfs args

[Eric Anderson]

On 08/02/06 22:59, Kevin Taber wrote:
> Hardware: HP DL380 G4, 3.2Ghz Xeon EM64T, Smart Array 6i, 3GB RAM, 2 logical
> drives: 2 x 36GB Ultra320 15k and 4 x 146GB Ultra320 10k
> RAID setup in question: 4 x 146GB Ultra320 drives ( roughly 300GB raid 5 )
> 
> 
> I'm setting this array up for samba use... Windows 2003 folders will
> redirect to a share.  I'm going with a raid stripe size of 128KB, what
> should my newfs args be?  I have heard mixed answers via IRC.

I think if I recall correctly you'll want to make sure your filesystem 
starts on one of the stripe offsets, so either at 0 bytes, or 128k byte 
offset.  If I recall, either phk@ or scottl@ knew the right magic for that.

Maybe this paper is related:
http://db.usenix.org/events/fast02/schindler/schindler_html/index.html

The best way to know for sure, is to test it with your type of workload 
(simulated or real).

Eric

-- 
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Eric Anderson        Sr. Systems Administrator        Centaur Technology
Anything that works is better than anything that doesn't.
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