Re: 3ware disk latency?

From: Alan Cox
Date: Wed Jul 26 2006 - 16:16:49 EST

Ar Mer, 2006-07-26 am 09:52 -0700, ysgrifennodd dean gaudet:
> On Mon, 10 Jul 2006, Jan Kasprzak wrote:
> > Does anybody experience the similar latency problems with
> > 3ware 95xx controllers? Thanks,
> i think the 95xx is really bad at sharing its cache fairly amongst
> multiple devices... i have a 9550sx-8lp with 3 exported units: a raid1, a
> raid10 and a jbod. i was zeroing the jbod with dd and it absolutely
> destroyed the latency of the other two units.

Even on the older 3ware I found it neccessary to bump up the queue sizes
for the 3ware. There's a thread from about 6 months ago (maybe a bit
more) with Jeff Merkey included where it made a huge difference to his
performance playing with the parameters. Might be worth a scan through
the archive.


To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at