----- Original Message
----
From: Kevin Whittaker <Kevin.Whittaker AT syniverse DOT com>
To: Mike Ferlote <merked AT rogers DOT com>; veritas-bu AT mailman.eng.auburn DOT edu
Sent: Wednesday, March 5, 2008 1:54:42 PM
Subject: RE: [Veritas-bu] VTL & NetBackup Best Practice
Mike,
Last January, I implemented a VTL (EMC
CDL720) with 35 usable TB. We did much study on the multiplex issue in
most instances the backup did perform faster when it was not multiplexed, but
with out a doubt the restore AND duplications speed is around 4 times as
fast. So, I am working towards having enough tape drives to stop all
multiplexing in my environment.
Here are my 2 issues....
I have a heavily clustered
environment with 27 Media Servers. Well, an ORACLE DB could fail over
from one server at any time. Well, when I originally setup the servers
with 1 or 2 drives each, there was not enough on a robot with 20 drives to have
the same robot on each media server. Well, what happens when the server A
goes down that points to robot 1, and the DB fails over to server B and it only
sees robot 2?!? I would have to scramble to make robot 1 visible on
server B. I did see something in the VTL that might allow me to transfer
the tape over from one robot to another and then I guess I would inventory the
robot.... but alas I am unsure.
Issue 2.... I do all my vaulting on my
master server. Since my media servers are also production servers, I do
not want to hit them with so much IO for duplication. So the master
server needed to have tape drives on each robot.
So, I after much thought and upgrading to
6.5 I realized that SSO is not so bad. In fact it is wonderful!
Media servers and join the SSO and pull out of it with no need to shutdown
netbackup on the master server! Configuring tape drives is one step away
by typing "tpautoconf -a".
Also, now I share the robots with in the
VCS clusters and make sure that each server in the cluster can see all the
robots. So, I can do restores with out any issues.
Lastly, I don't have to generate 13 robots
with 20 tape drives each to turn off multiplexing! Yes, that is how many
tape drives I would have needed to meet that demand.
So, I recommend that you don't turn away
from SSO. I believe it is still a great feature and runs so much smoother
in 6.5.
P.S..... Actually I would say NOT to
purchase a VTL. I believe with all the new great features in NB 6.5, make
the Disk Staging Units to be the best options for most people.
P.S.S.... Remember when you turn off
multiplexing on the VTL, you will HAVE TO over subscribe the number of tapes,
so that you don't run out of media!
Please feel free to e-mail me any other
questions.
Kevin
From: veritas-bu-bounces AT mailman.eng.auburn DOT edu
[mailto:veritas-bu-bounces AT mailman.eng.auburn DOT edu] On Behalf Of Mike Ferlote
Sent: Wednesday, March 05, 2008
6:25 AM
To:
veritas-bu AT mailman.eng.auburn DOT edu
Subject: [Veritas-bu] VTL &
NetBackup Best Practice
Hi,
I am currently testing my NetBackup environment to backup to VTL. We are seeing
great backup performance but it seems like it requires a slight re-architecture
to the current environment. I am being told to eliminate multiplexing... You
can multiplex to a virtual drive but when it comes time to restore and to
duplicate off to physical tape from a virtual cartridge that was multiplexed
the performance is not very good. The Vendor said that multiplexing should be
eliminated and instead of increasing multiplexing you can simply create
additional virtual drives when needed. Since adding virtual tape drives in
theory has no cost associated with it why not do this and eliminate
multiplexing and SSO all together (that is the approach/mentality).
So my question to the forum is have others deployed VTLs in a similar fashion
(i.e. MPX = 0) and how have things scaled and is there any associated
management headaches? The couple con's of the above approach in my mind would
be:
* Slower responding NBU GUI because there will be so many devices it will have
to manage/query
* More BPTM processes since each tape drive in use requires one an additional
BPTM process
* Slower backups on a per stream basis (which is OK because you have many
drives I guess)
Can anyone comment if they foresee other drawbacks to this approach or have
best practice recommendations?
Thank in advance for any feedback...
-Bill