[Veritas-bu] Has anyone done benchmarking of any sort with..

[Kevin Whittaker]

Ah... Yes I see where you are going.... But my way will just put the
image on the tape, no multiplexing at all.  I have a Virtual Tape
Library, and I am in the process of creating 5 robots with 20 drives
each.

To avoid multiplexing you have to dedicated a drive to each channel, and
that is what setting the MPX=1 does.

When you are limited on tape drive resources.... You can not do this.  I
used to just have my L700 with 11 9940B drives, and could have never
considered this with the fact that I backup over 35 databases.  But now,
with the VTL I can configure as many drives as I want to configure.

So to answer the question, un multiplexing will commit 1 drive to each
channel.  You can not multiplex different backups onto the same drive at
the same time.

Kevin 

-----Original Message-----
From: Justin Piszcz [mailto:jpiszcz at lucidpixels.com] 
Sent: Friday, July 27, 2007 8:46 AM
To: Kevin Whittaker
Cc: veritas-bu at mailman.eng.auburn.edu
Subject: RE: [Veritas-bu] Has anyone done benchmarking of any sort
with..



On Fri, 27 Jul 2007, Kevin Whittaker wrote:

> Oh... Sorry about that.
>
> That is the easy part.
>
> Under the Schedule, within the policy, I changed the media 
> multiplexing to 1.  The RMAN script starts 4 channels, and sees the 
> schedule says only 1 multiplex then it sends them to different tapes.

This is good in a sense, but say you have 10 tape drives for example.
If you are multiplexing other backups with the DB backups, does the RMAN
policy write with LEVEL 1 multiplexing to separatae tapes and the other
backups still take place for the other (assume MPX=4) 3 levels of
multiplexing on the drive? Or does the MPX=1 job utilize the entire tape
drive?  Does it make sense what I am mentioning?

Essentially you'd want separate tape media IDs for each server but you
still want other servers writing for the other 3 levels of MPX on that
tape.

Justin.