[Veritas-bu] Fast backup to tape but slow backup to disk on NBU 5.1MP3

2005-08-22 14:17:43
Subject: [Veritas-bu] Fast backup to tape but slow backup to disk on NBU 5.1MP3
From: mclausen AT csit.fsu DOT edu (Matt Clausen)
Date: Mon, 22 Aug 2005 14:17:43 -0400
Matt Clausen wrote:
> This has indeed been a very valuable thread to me.... and I've 
> implemented a bunch of the suggestions given so far and will have some 
> results to send back to the list in a little while... 

Well, here's the final setups that seem to be working for me now....

First off, there is a lot of conflicting information out there on the 
net, where some people say to do it one way and someone else says 
something totally in the opposite direction... So while this may work 
for me, it might not work for you all that well.... That being said...

I had a 16x250GB SATA Array which originally I had setup as a single 16 
disk RAID5 unit. I fragmented this array up into 3 5-disk RAID3 groups 
with only 1 LUN (the 16th disk is a global spare).

Then using Veritas Volume Manager, I striped the LUNs together into a 3 
disk 256k stripe RAID0 set and put a Veritas File System on there.

Under Netbackup I made it so only ONE job goes to this disk at a time. 
As someone mentioned, SATA is good at sequential writes not random 
writes so when one job goes at a time, I am seeing 10-15Kb/sec transfers 
(still not what I would expect for a disk based backup but better then 
what I was seeing).

It'd be interesting to see if a Fibre Channel to SATA setup would be 
better then the SCSI to SATA based one I am using right now.. or if a 
straight up SCSI based solution would offer better performance.

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