Hello Zoltan,

First is to know if this volumes are for sequential or random access.

In our configuration, we have 3 100Go volumes for random access and more than 
500 volumes of 20Go  for sequential access.

The first avantage off have many small volumes cause TSM using as many volumes 
is want. (maximun mount point for the devclass)

The second, is to be able to reclaim very quickly such volumes. In our case, we 
reclaim with a threshold=40.


Cordialement, 
Regards,
Grégory


________________________________________
De : ADSM: Dist Stor Manager [ADSM-L AT VM.MARIST DOT EDU] de la part de Zoltan 
Forray/AC/VCU [zforray AT VCU DOT EDU]
Date d'envoi : jeudi 17 février 2011 19:15
À : ADSM-L AT VM.MARIST DOT EDU
Objet : [ADSM-L] How many disk volumes are too many?

I am aware of the TSM design that says the more disk volumes you have, the
more it will spread out the I/O  for better performance.  I also realize a
lot of this doesn't really apply what with RAID-5, EMC SAN, multi-terabyte
storage, etc.

So, at what point does having lots of smaller volumes (for a disk LZ), not
give you any more benefit, I/O wise?

I have a 5.3TB SAN space on my new 6.2.2.0 server.  Originally, I started
formatting 200GB volumes then moved to 300GB, up to 25-volumes.

Now I am adding another 5.3TB space and was wondering if I should continue
with 300GB or jump to 500GB?

Simultaneous sessions should not be an issue since most of these backups
are Domino TDP and therefore single thread.  I don't think there is a peak
of more than 60-simultaneous sessions.

The TSM server is a Dell T710 with 48GB RAM and 15K internal disk for the
DB & Logs.

Your thoughts?
Zoltan Forray
TSM Software & Hardware Administrator
Virginia Commonwealth University
UCC/Office of Technology Services
zforray AT vcu DOT edu - 804-828-4807
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