[ale] Disk IO Question

[Greg Clifton]

What about bus contention. I'm not familiar with the IBM model you
mentioned, but if you are running PCI cards (32bit, 33MHz) then you do have
a bit of a bottleneck there, plus if there are other expansion cards in the
system they can slow things down.
GC


On Thu, Oct 29, 2009 at 5:10 PM, James Taylor <
James.Taylor at eastcobbgroup.com> wrote:

> Make that 15k RPM *SAS* drives...
>
> >>> "James Taylor" <James.Taylor at eastcobbgroup.com> 10/29/2009  05:04 PM
> >>>
> I would suggest that your datapaths are not going to be the bottleneck with
> SATA drives.
> I had a client running SATA for several years on an iSCSI  appliance, and
> one day we hit a brick wall with the mail performance.  We spent weeks
> trying to tune the I/O paths to deal with it, and when we looked at the
> actual SATA drive transfer capacity, we realized the drives were the
> problem.
> We replaced the drives with 15k RPM SATA drives, and life has been good
> ever since.
> Check your drive specs and see if that's where the limitation really is.
> -jt
>
>
> James Taylor
> The East Cobb Group, Inc.
> 678-697-9420
> james.taylor at eastcobbgroup.com
> http://www.eastcobbgroup.com
>
>
>
>
> >>> <mmillard1 at comcast.net> 10/29/2009  04:49 PM >>>
>
>
> I have a Suse OES server running on an  IBM 346with 2 gig of RAM.   I've
> installed two Addonics Multilane SATA cards connect with Multilane cables to
> external SATA enclosures housing 4 WD Caviar Green 1.5 TB Drives.
>
>
>
> I have about 1.8 TB of Data on one Enclosure which changes daily.  My plan
> was to copy the 1.8 TB to the second enclosure daily and send the drives in
> that unit off site.
>
>
>
> My expectation was that by having 4 independant SATA paths per unit  would
> give me  substatial performance when moving data between these units.
>
>
>
> I'm seeing a constant speed of about 60 gig per hour.  This is much slower
> than I expected.  Have any of you done anything like this? Is this the kind
> of performance I should expect?  Hopefull some of you bright people can
> share some wisdom with me.
>
>
>
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