> -----Original Message-----
> From: James Manning [mailto:[EMAIL PROTECTED]]
> Sent: Friday, February 25, 2000 1:24 PM
> To: Gregory Leblanc
> Cc: [EMAIL PROTECTED]
> Subject: Re: SW-RAID or Compaq HW-RAID?
>
>
> [ Friday, February 25, 2000 ] Gregory Leblanc wrote:
> > > Then, how much slower (not faster I guess :) Smart Array
> 221 would be
> > > than SW-RAID (single P3-500)? And can I do all SA-221
> maintaining from
> > > Linux or do I need to reboot to dos? New official home
> > > (ftp://ftp.compaq.com/pub/products/drivers/linux/) does
> not have too
> > > much documentation..
> >
> > That sort of depends on what the server is doing. Software
> RAID performance
> > is dependant on how many CPU cycles you have free. I.E.
> software RAID is
> > probably BAD for DNS servers, and database servers.
>
> 2 things:
>
> 1) this brings up an interesting point about prioritization.
> Can someone
> do tiobench runs with a totally idle machine and then with
> something
> pegging the processors? (load avg = # of processors)
Does anybody have a nice script to run tiobench through it's paces, and
collect results? I'm going to try that SPARC patch tonight, and run RAID5
through it's paces. I suppose I'll need to find a nice way to keep the
processors busy, maybe compiling something into /dev/null...
>
> 2) If the avg load on the machine is < 80% of (# of processors) you're
> likely to have the spare cycles, even for DB and DNS
> servers. Depending
> on access patterns and usage, even the most heavily pegged
> DB server
> may have the spare cycles as current access patterns
> bottleneck the DB
> activities at other places (disk, scsi bus, whatever)
Isn't load avg just the number of jobs that are waiting? My mail servers
have a load avg of about 5, but they're not at all CPU bound, it's all about
I/O. Ahh, how I wish I had linux on that DS20 in the back room...
>
> A nice study of how load (both CPU and other I/O, like to a
> network PCI
> GigE card) would be most enlightening.
Well, our most heavily connected machines here have a single 100MBit
connection. Anybody have some gigabit (copper of fiber) equipment they want
to loan me for some testing? :)
Greg
