Hi Steve

We are a Windows based shop running 6.0 MP3. We use an HP MSL6060
library with 4 LT03 drives. When backing up individual servers over a
gigabit network we can get 80-90MB/s especially when backing up
databases. During the overnight backup run when many servers backup
together we get up to 60MB/s.

The vault duplication process runs at up to 150MB/s with most being
around the 100MB/s.

I don't know if you have had a chance to play with the Netbackup buffers
but that was where the biggest gains were for us. Ours are currently set
to:-

SIZE_DATA_BUFFERS_DISK          1048576
NUMBER_DATA_BUFFERS             64
NUMBER_DATA_BUFFERS_DISK        64
SIZE_DATA_BUFFERS                       262144
NET_BUFFER_SZ                   1048576

We had a play with multiplexing but found that the gains during backups
were almost negated by the extra time taken to do the vault process.
Since the time pressure for us was during the vault process not
overnight backups we turned it off again.

Regards

Richard

-----Original Message-----
From: veritas-bu-bounces at mailman.eng.auburn.edu
[mailto:veritas-bu-bounces at mailman.eng.auburn.edu] On Behalf Of Steve
Kirkpatrick
Sent: Friday, 22 December 2006 6:56 am
To: Austin Murphy
Cc: veritas-bu at mailman.eng.auburn.edu
Subject: Re: [Veritas-bu] LTO-3 throughput expectations

Thanks for the info Austin.  You pretty much confirm what I have been
reading.

Anyone else have an idea of why I can only seem to drive the tape drives
at 12.5MB/sec when duplicating tapes on the master server?  The server
itself is not loaded during this activity.  It seems that bpduplicate
should be able to read at max speed and write at max speed
simultaneously especially since the drives and server are connected over
a 2gb/sec SAN.

I guess the long-term solution is to go with a disk-based device (such
as the Data Domain) for the initial backups and then archive to tape
from there.

Also, what about the bpduplicate performance when duplicating
multiplexed tapes?  How about restores from the same?  Am I just moving
the bottleneck from one place to another?

Any links to info that will educate me on the subject are appreciated.

Thanks again,
Steve.


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