RE: 3Ware 9550SX and latency/system responsiveness

["Ross S. W. Walker" <rwalker@xxxxxxxxxxxxx>]

Feizhou wrote:
> 
> Simon Banton wrote:
> > At 17:34 +0800 14/9/07, Feizhou wrote:
> >> .oh....do you have a BBU for your write cache on your 3ware board?
> > 
> > Not installed, but the machine's on a UPS.
> 
> Ugh. The 3ware code will not give OK then until the stuff has 
> hit disk.
> 
> > 
> > I see where you're going with larger journal idea and I'll 
> give that a go.
> 
> Well, I do not think it will help much with a larger 
> journal...you want 
> RAM speed, not single 250GB SATA disk speed.

Yes, a write-back cache with a BBU will definitely help, also your config,

> 4x Seagate ST3250820SV 250GB in a RAID 1 plus 2 hot spare config

is kinda wasteful, why not create a 4 disk RAID10 and get a 5th drive for
a hot-spare.

Also think about getting 2 internal SATA drives for the OS and keep the
RAID10 as purely for data, that should make things humm nicely and to be
able to upgrade your data storage without messing with your OS/application
installation. It wouldn't cost a lot either, 2 SATA drives + 1 SAS drive.

-Ross

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