Hi Wes

Yours are exactly my reasons for using RAID-5 instead of the other choices.
EMC, for instance, has worked very hard to optimize its RAID-5
implementation.  I believe that RAID-5, coupled with ATA disks, is a
compelling backup-to-disk platform.

tl

-----Original Message-----
From: Wes Ono [mailto:wono AT legato DOT com]
Sent: Thursday, February 20, 2003 4:25 PM
To: 'Legato NetWorker discussion'; 'lemons_terry AT EMC DOT COM'
Subject: RE: [Networker] Staging from a partition or of the folder - File
device?



Terry,

I beg to differ on your RAID recommendation.

I would recommend AGAINST RAID-5 for a file-type device.  Each write to a
RAID-5 set results in a write-read-write sequence because of the need to
recalculate and rewrite the parity strip.  This will negatively impact your
performance.

RAID-0 (striping) gives good performance, but had no redundancy in case of
disk failure.  RAID 1+0 (striping across mirror sets) gives good performance
and protection against disk failure, but tends to be expensive, as you need
2*n disks.

Wes

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