Re: Disk speed comparison

[Roy Sigurd Karlsbakk <roy@karlsbakk.net>]

> > I have an array with 6 2TB drives plus a spare. While this works
> > well, I can from the munin graphs at
> > http://munin.karlsbakk.net/munin/karlsbakk.net/smilla.karlsbakk.net/index.html
> > that the WD2001FASS drives (sd[bcfg]) perform some 30% better than
> > the Hitachi HDS723020BLA642 drives (sd[eh]). The drives are on a
> > mixed set of controllers, so this shouldn't be relevant. Since they
> > all are specified to spin on 7200RPM, I find it wierd that the
> > performance difference shown by the Munin graph is so big.
> >
> > Anyone seen something similar?
> 
> Go the the manufacturers web sites and find the spec sheets for the
> drivers.
> 
> They will likely list a min speed and a max speed for how fast data is
> passing under the head depending on if it is the inner or outer track.
> 
> It basically comes down to if all is working exactly right, the number
> of bytes passing under the head times rpm, so if one disk has a higher
> bit density the rate will be larger, and this varies quite a bit from
> disk to disk.

Thanks for the replay

WD2001FASS: 4x500GB platters
HDS723020BLA642: 3x667GB platters

- Shouldn't higher density normally mean higher speed?

Vennlige hilsener / Best regards

roy
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Roy Sigurd Karlsbakk
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roy@karlsbakk.net
http://blogg.karlsbakk.net/
GPG Public key: http://karlsbakk.net/roysigurdkarlsbakk.pubkey.txt
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