Re: [gentoo-user] Tuning SCSI disks-App like hdparm available?

[Ow Mun Heng]

On Mon, 2006-03-13 at 08:39 -0700, Richard Fish wrote:
> On 3/13/06, Ow Mun Heng <Ow.Mun.Heng@×××.com> wrote:
> >         I recently got a bunch of (old) scsi disks and would like to get the
> > most out of them. They are 7200 18GB scsi disks which hdparm reports up
> > to 18MB/s of transfer rate. (vs 30MB/s on my 5400 80GB laptop drive and
> > 24MB/s on a 7200 200GB IDE Drive)
> >
> > I'm wondering if there are applications which can be used to tune the
> > disks for better performance?
>
> I don't think there is much tuning that can be done, other than
> putting them in a RAID0 array.

Wouldn't Raid5 be a better choice? Although there is the added Parity
which does give some fault tolerance. 

Actually, since you brought it up, I've got 4 drives, 1 I'm using for
the OS. The other 3, I'm undecided.

It's either.
3x18GB = 54GB in a LVM2 array (/storage) (JBOD I guess)

or
3x18GB Raid 0 = 54GB but lose _all_ data if any disk fails. 

Not an option I suppose.

>  SCSI already does DMA, so as long as
> they are attached to the fastest controller that the drives support,
> you are probably maxed out on throughput.

Sigh.. That's still low comparatively compared to the newer generation
of drives (esp SATA which give up to 80-100MB/s transfers)

>
> BTW, 24MB/s on a 7200rpm 200G drive on an IDE channel seems very, very
> low.

It is isn't it? Then again, it's also attached to a Pentium II system.
(I was comparing apples to apples)

Pentium II 300Mhz w/ SCSI disks - 18MB/s (18GB Scsi 7200rpm)
Pentium II 300Mhz w/ IDE disks - 24MB/s  (200GB IDE 7200rpm)

>   That number should be more like 65MB/s.  Unless this is actually
> in a USB enclosure...

Nope.

-- 
Ow Mun Heng
Gentoo/Linux on DELL D600 1.4Ghz 1.5GB RAM
98% Microsoft(tm) Free!! 
Neuromancer 11:13:22 up 2 days, 13:16, 4 users, load average: 0.98,
0.70, 0.36 


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