[lug] Re: advice on disk configuration

[Zan Lynx]

On Mon, 2003-11-17 at 20:30, pjr at ucar.edu wrote:
[snip]
> Now my question is, are the numbers I
> quote below reasonable for a high performance PCI bus, controller and
> ATA/100 disk? They are only 50% of the slowest theoretical transfer
> rates you quote above, and much less than the numbers you quote for a
> 66Mhz PCI bus (which is what I have). I poked around a bit on machines
> at work, and the fastest speeds I found on those machines were order
> 70MB/sec. So my numbers are 20% slower than the fastest rates I came
> across. 
> 
> Phil
> 
> > hdparm -d1 /dev/hde
> > hdparm -tT /dev/hde
> > 
> > /dev/hde:
> >  Timing buffer-cache reads:   2624 MB in  2.00 seconds = 1312.00  MB/sec
> >  Timing buffered disk reads:  168 MB in  3.00 seconds =  56.00 MB/sec
> > 

Well, I have some samples I can share with you.  Here at home my RAID 5
of 4 120 GB, 7200 rpm IDE drives rates:
 Timing buffer-cache reads:   984 MB in  2.00 seconds = 491.83 MB/sec
 Timing buffered disk reads:  224 MB in  3.03 seconds =  74.01 MB/sec

I don't have it here, but at work I tested a Seagate X.15 SCSI drive,
and it rated around 68 MB/sec.

Also at work, a single SATA 80 GB drive rated about 52 MB/sec.

For a single disk, I think your 56 MB/sec is a good speed.
-- 
Zan Lynx <zlynx at acm.org>
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