Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
On Wednesday 04 October 2006 19:30, Lars Ellenberg wrote:
> / 2006-10-04 18:36:40 +0200
>
> \ Peter Sabaini:
> > > > # hdparm -t /dev/cciss/c0d0
> > > >
> > > > /dev/cciss/c0d0:
> > > > Timing buffered disk reads: 208 MB in 3.03 seconds = 68.69 MB/sec
> > > >
> > > > It could be better, but its reasonable I think?
>
> well, actually, write performance would be more interesting.
> make sure that the raid is not rebuilding at the same time.
>
> also, the cciss controler likes high values for
> max-buffers
> max-epoch-size
> unplug-watermark
Ok, that helped -- I now get around 23MB/s which is not great but a lot better
than before :-)
For the record I now use
sndbuf-size 1M;
max-buffers 32768;
max-epoch-size 16384;
unplug-watermark 32768;
I cant test right now but from an earlier naive test (dd if=/dev/zero
of=zero.dat bs=1M count=4096) write performance was around 32MB/s for the
disk device (ext3 on top of lvm), so thats the limiting factor now I guess.
Any advice on getting more out of that cciss? :-)
Thanks a lot,
peter.
--
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Peter Sabaini
ARC Seibersdorf research GmbH
Biomedical Engineering / eHealth systems
Reininghausstrasse 13/1, 8020 Graz, Austria
T: +43(0)316 586570-55, F:+43(0)316 586570-12
peter.sabaini at arcsmed.at, http://www.arcsmed.at/ehs