[lug] Promise Vtrak performance

[George Sexton]

It would be more helpful if instead of saying performance was abysmal, 
you gave us some numbers out of a benchmark program like bonnie++.

SW raid 1 runs around 50MB/Sec, while HW RAID 1 runs around 60MB/Sec.

What is yours doing?

Rob Nagler wrote:
> We have two Promise Vtrak 12110 enclosures with 12 x 500MB SATA drives
> configured with RAID5 as a single array and 3 logical drives (2 x 2TB,
> 1 x 1TB).  Performance is abysmal now that we've been using this set
> up for a while.  We are only using one of the 2TB logical drives; the
> other two drives are mostly empty.
> 
> We are rsyncing nightly for backups from a variety of machines.  At
> first this was working just fine.  As the file system grew to
> hundreds of inodes, rsync got slower and slower.  I don't think it is
> rsync as the data mix on the machines we are backing up is not that
> different.  The rsync is hung in a device wait on the backup
> machine pretty much any time I look.
> 
> The one complication is taht we are linking with cp --archive --link
> to keep historical copies.  This means static inodes are being
> reference hundred or so times.  Static inodes make up most of the data
> mix so I suspect there's some behavior relating to how ext3
> distributes inodes and how the vtrak distributes its data.
> 
> Even simple operations, like rm -rf on old backups or du, take hours
> and sometimes days to run.
> 
> I have seen references on the net to slow performance on the Promise
> enclosures (which are Linux boxes, btw).  Promise has asked for lots
> of information, but they haven't provided any answers.
> 
> The performance is abysmal on both RH7.2 on RHEL4.5 (CentOS).  It
> doesn't matter if the machine is busy or idle.  It can be doing
> nothing, and a du will not complete in an hour, when I think it should
> (and does in similar mixes on much slower machines).
> 
> Rob
> 
> 
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-- 
George Sexton
MH Software, Inc.
Voice: +1 303 438 9585
URL:   http://www.mhsoftware.com/