Storage unit versus storage unit group

[perez_cmz]

Is there any reason why I wouldn't always use a storage unit group in an SLP, as opposed to just a storage unit ?

[Stumpr2]

You may want to keep specific configurations for a particular client's backup. You may want to ensure a storage unit is readily available for particular group or singular client's backup.

[Nicolai · Accepted solution]

Almost all mine SLP's uses storage unit groups - and I got a lot. There is nothing wrong with the strategy of using storage unit groups. The increased load on the resource broker is gladly paid (as mentioned in the SLP best practice).

[Stumpr2]

ayep. thats the norm. there may be more exceptions than I gave but I cant think of any.

[revarooo]

If you decide to go with STUG, do not overload them. Keep them fairly small.

[perez_cmz]

What is considered small ?

[mph999]

No more than 5 storage units in a storage unit group - and I originally heard that from Enginering, so in my mind at least, if you get issues by having more it might not be fixable. For certain, I've seen busy environements have major issues because of silly numbers of STUs in STU groups.

[huanglao2002]

Symantec suggest not more than 5-6 STU in a storage unit group.It's need consume more resource to select STU.

[Marianne]

STUG is not supported with AIR. See http://www.symantec.com/docs/HOWTO86999

If creating an SLP for Auto Image Replication, do not select a storage unit group. Auto Image Replication does not support replicating from a storage unit group. That is, the source copy cannot be in a storage unit group. 

[watsons]

Not only AIR, but also optimized duplication:

http://www.symantec.com/docs/HOWTO70482

I won't use STUG unless really necessary anyway...

[Nicolai]

The number isn't documented in the manual. Is it possible to get the number confirmed - the rumor may be outdated by now.

[mph999]

Hi Nicolai,

I'll see if I can find which document it is in - I think it apearred in a TN at some point, but I seem to recall I did see it in one of the manuals - if thiis was one of the 'best practices' or 'performance and tuning' I can't remember.  I think it was a 'recommendation' as opposed to a 'limit' but from the conversations I have had / heard of with very very experienced guys, they talk about it as a limit.

Not that long ago 2 - 3 months maybe, I was actually talking with one of Engineers in the US who specialises in performance issues - I'm fairly sure this popped up in the conversation and the limit was still 5. 

I'm 99.9% sure this hasn't changed - this topic pops up quite frequently in the office ...

I'll have a dig about and see if I can find it.

M

[mph999]

Hmm looks like I remembered incorrectly, I can only find it in a technote.

http://www.symantec.com/docs/TECH64845

Hope this is ok for you.

M

[RadovanTuran]

Is the number of STUs in STUG an issue if simple round-robin is used?