[CentOS] Write performance with 3ware 9550

Joshua Baker-LePain
Thu, 12 Oct 2006 20:25:54 -0000

On Thu, 12 Oct 2006 at 4:22pm, Bowie Bailey wrote

> I have two identical servers.  The only difference is that the first
> one has Maxtor 250G drives and the second one has Seagate 320G drives.
>
> OS: CentOS-4.4 (fully patched)
> CPU: dual Opteron 280
> Memory: 16GB
> Raid card: 3ware 9550Sx-8LP
> Raid volume: 4-disk Raid 5 with NCQ and Write Cache enabled
>
> On the first server I have decent performance.  Nothing spectacular,
> but good enough.  The second one has about 1/3 the write speed.  I
> can't find any difference between the systems.  Both of them have the
> same stripe size, both have ext3 filesystems, both have write caching
> and NCQ turned on.  I have already increased the read ahead setting to
> 16384 on both servers.

Turn off NCQ.  Last I knew, this was still 3ware's recommendation.

--
Joshua Baker-LePain
Department of Biomedical Engineering
Duke University