[Gllug] Computer shopping

[Anthony Chapman]

On Mon, 2003-07-28 at 16:29, Andy Farnsworth wrote:
> > If you have a real RAID controller (i.e. not anything made by Adaptec or
> > rebadged by Dell), the number of disks is utterly irrelavent.
> 
> I don't agree with this, the throughput of a single disk is limited while
> multiples of these disks same disks will agregate their performance if used
> appropriately.  If you stripe or mirror these disks, you will find that read
> performance increases and for striping, so does write performance.  A 2
> drive RAID will be swamped by an 8 drive RAID almost every time, provided
> you are striping or striping and mirroring (or parity striping).  2 drives
> with 25 Mb throughput each have an agregate throughput of 50 Mb (though you
> don't get 100% efficiency adding disks, going from one drive to two is
> pretty close, on sequetial reads that is)  An 8 drive array will have a
> troughput of about 200 Mb.  Remember that these are all maximums and real
> world performance may and WILL vary for the RAID AND the single drive.

More CPUs = better performance, but I think his point was that if you
have a good RAID controller then you won't have to suffer increased CPU
use to get that performance. 

-- 
load "vmlinux.el",8,1

-Anth


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