[CentOS] Write performance with 3ware 9550
William L. Maltby
CentOS4Bill at triad.rr.com
Mon Oct 16 21:05:52 UTC 2006
On Mon, 2006-10-16 at 16:24 -0400, Bowie Bailey wrote:
> William L. Maltby wrote:
> > On Fri, 2006-10-13 at 11:44 -0400, Bowie Bailey wrote:
> > > Kirk Bocek wrote:
> > > > <snip>
WOW! Do I have a typo bug or what?
> > > Right now, I am not looking for maximum performance. I am just
> > > trying to determine why there is a 3x difference in write
> > > performance between two identical machines.
> > 60 vs. 40 conductor cables on UDMA? have you wiggled/reseated them?
> These are SATA drives, but I have checked the cable connections.
> > /var/log/messages BogoMips the same?
> I'm not familiar with this.
In /var/log/messages (and dmesg too, IIRC) is a "rating" of performance
for the CPU. "BogoMIPS" is the name. Also in there is "Detected xxxx.x
MHz processor". I was thinking if there is any substantial difference,
maybe that is a clue.
E.g. if PS is weak, one of the processors may run slow. I just finished
chasing some junk caused by a weak PS. AMD 2200+, s/b 1.8GHz, was
Popped in a 575 watt (425 continuous) PS and all is good again.
> > Mem config same?
> Yep. They've both got 16GB of RAM (6GB allocated to Huge Pages and
> about 9GB free).
In BIOS, same timings on memory (CAS, etc.)?
> > Same "load". Does top in a "long" screen show any diference in number
> > of loads or total load being imposed? Keep an eye out for excessive
> > wait channels in top (have to change defaults of fields displayed and
> > order) or in ps?
> I haven't seen that. I'll keep an eye on it next time.
> > Are you using the sar reports, which can be helpful in the case of
> > large unknowns.
> I haven't used the sar reports. Sar tends to be a bit cryptic. If
> you can give me a useful command line, I'll check it out.
It has been so long since I did admin jobs for real, I can't help you.
But there's lots of strong admins here.
Guys/gals, help the man out here?
Sorry I can't be more help. I just acquired my first two SATA drives and
have yet to install and start using them.
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