Why would it be 240 Storage Units?
The way I would figure it is this:
10 media servers 96 drives = 9.6 drives/media server
4.8 drives per stu = 2 stunits per media server
9 media servers with (2) 5 drive STUs and one media server with (2) three
drive STU.
Are you in an SSO environment?
Maybe I'm missing something...
BTW:
The essence of your email has touched on a hot button for me, this something
I have asked Veritas to deal with for quite some time.
David
<><><><><><><><><><><><><><><><><><><><>
David A. Chapa
NetBackup Consultant
DataStaff, Inc.
http://www.consulting.datastaff.com
847 413 1144
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-----Original Message-----
From: veritas-bu-admin AT mailman.eng.auburn DOT edu
[mailto:veritas-bu-admin AT mailman.eng.auburn DOT edu]On Behalf Of Lundy, Mark
Sent: Thursday, September 27, 2001 7:58 AM
To: 'Veritas Support List Server'
Subject: [Veritas-bu] How many Storage Units do you have defined?
We seem to have run into a storage unit limit. We have 4 robots (32, 32, 16
and 16 drives in each) and 10 media servers. A Veritas consultant
recommended that we define storage units in a round-robin manner with 4
drives each so that the load gets spread out over the media servers and
robots as much as possible.
So, 96 drives divided by 4 equals 24 4-drive possible stus for our entire
robots. 24 4-drive stus times 10 media servers equals 240 storage units
total. The stu definition looks something like this:
mediaserverArobot1 (4 drives)
mediaserverBrobot2 (4 drives)
mediaserverCrobot3 (4 drives)
mediaserverDrobot4 (4 drives)
mediaserverErobot1 (4 drives)
mediaserverFrobot2 (4 drives)
mediaserverGrobot3 (4 drives)
mediaserverHrobot4 (4 drives)
mediaserverIrobot1 (4 drives)
mediaserverJrobot2 (4 drives)
mediaserverArobot3 (4 drives)
mediaserverBrobot4 (4 drives)
mediaserverCrobot1 (4 drives)
and so on until all 240 are defined. This Veritas consultant informed us
that stus are picked in alphabetical order, Thus, when a backup stream is
started, as 4 drives become busy, another stus is chosen for any more jobs
and the load is spread out over not only the media servers, but over the
robots as well.
The problem with this config is, according to Veritas, every backup job has
to traverse the stus list and confirm its ability to communicate with each
stu As you can imagine we have a large environment and over 3000 backup
jobs run nightly. 3000 * 240 = way too many for our E4500 master server to
deal with and all jobs expire with 196 errors.
Now, finally to my question, what is the most stus any of you have defined?
I backed my config down to 40 stus, with each stu defined with the number of
drives in the library and it is working just fine. However, that doesn't
accomplish the load balancing that I desire. I.e, media server one will
handle all backup requests until robot one busies all of its 32 drives
before the any jobs go to media server 2 and/or robot two. TIA.
Mark
-
Mark W. Lundy
I.T. Recovery Management
Work: 816.965.1131
FAX: 816.965.1042
<mailto:mlundy02 AT sprintspectrum DOT com> mlundy02 AT sprintspectrum DOT com
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