Message-ID: <5487C422.2000306@catalyst.net.nz>
Date: Wed, 10 Dec 2014 16:55:14 +1300
From: Mark Kirkwood <mark.kirkwood@catalyst.net.nz>
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Subject: Re: 8xIntel S3500 SSD in RAID10 on Dell H710p
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On 10/12/14 12:28, Strahinja Kustudić wrote:

>   * These tests are with the H710p controller set to write-back (WB) and
>     with adaptive read ahead (ADRA). I ran a few tests with
>     write-through (WT) and no read ahead (NORA), but the results were worse.

That is interesting: I've done some testing on this type of card with 16 
(slightly faster Hitachi) SSD attached. Setting WT and NORA should 
enable the so-called 'fastpath' mode for the card [1]. We saw 
performance improve markedly (300MB/s random write go to 1300MB/s).

This *might* be related to the fact that 16 SSD can put out more IOPS 
than the card can actually handle - whereas your 8 S3500 is probably the 
perfect number (e.g 8*11000 = 88000 which the card can handle ok).


[1] If you make the change while there are no outstanding background 
operations (array rebuild etc) in progress (see 
http://www.flagshiptech.com/eBay/Dell/poweredgeh310h710h810UsersGuide.pdf).

Cheers

Mark


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