RAID-3 is a bad idea, this is what EMC recommends-- we had the same 
problem with a CX500, BAD BAD BAD idea.  Use RAID5 and you'll see much 
faster speeds (and use more disks in each RAID-set as well).

Justin.

On Fri, 27 Apr 2007, Navarro, Eddy A. wrote:

> Gurus,
>
>
>
> I've been doing some performance testing of backing up to a Disk Storage
> Unit of SATA disk.  We have the following:
>
>
>
> Netbackup 5.1 MP6
>
> SunFire V800 running Solaris 9 with 8GB RAM
>
> Veritas Volume Manager 4.1
>
> CX700 array with 500GB 7200rpm SATA drives
>
> Emulex LP9000 HBA
>
>
>
> I've been doing all sorts of tweaking, from adjusting the disk buffer
> files per http://seer.entsupport.symantec.com/docs/273532.htm, cranking
> up the write cache on the CX700 to over 2GB, changing the RAID layouts,
> but I just cannot get performance better than 15MB/s.  Surely backing up
> to SATA can produce better results than that?
>
>
>
> Currently, I've got six 500GB LUNs each in their own 4+1 RAID group
> using RAID3.  These LUNs are then striped into a RAID0 volume using
> Veritas Volume manager (at first I tested with a striped MetaLun on the
> array, but results were no different).
>
>
>
> As stated, I've tweaked till I'm blue in the face but I can't seem to
> squeeze anything above 15MB/s.  Any hints as to what I could be
> overlooking?  Performance is not looking good compared to our NDMP
> backups to LTO-2 tape which run at the nice clip of ~35MB/s.
>
>
>
> Thanks,
>
> Eddy
>
>