Hi John,
        We are running TSM 6.1.3.3 on AIX 6.1 and we already increased TSM DB2 
Database space twice using the same Filesystem (directory). TSM documentation 
only mention the use of a new filesystem to increase the size of the DB using 
EXTEND DBSPACE new_filesystem . I don't think extending TSM DB across 2-3-4 
filesystem would spread the I/O more then using only one filesystem based on 
the fact that it is the number of disk your DB is spread across that will make 
the difference. Your LUNs need to be spread across different raid groups in 
order to provide the best performance. I really think one directory can be as 
efficient as 2 or 3.   

Pierre Billaudeau
Analyste en stockage
Livraison des Infrastructures Serveurs
Société des Alcools du Québec
514-254-6000 x 6559

-----Message d'origine-----
De : ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU] De la part de 
John D. Schneider
Envoyé : 11 mai 2010 16:21
À : ADSM-L AT VM.MARIST DOT EDU
Objet : [ADSM-L] TSM 6 database space performance question

Greetings,
   I have a customer running TSM 6.1.3 on a Linux RedHat 5.4 server.
They are using high-performance SAN attached disk for the TSM database
and logs.  They have created the TSM database all in one directory under
one filesystem.  Recently then needed to add more space, and they carved
out a lun from another RAID group, and then added that lun to the
existing filesystem.  TSM shows that it now has the additional space,
but it is still all under one directory.
   In reading the Performance Guide and Admin Guide, they both recommend
spreading the data out over multiple directories, putting each directory
behind separate disks/luns.  This certainly makes sense to spread the
I/O out over multiple luns, and I get that.  But is there anything wrong
with the way my customer has done it?  They are using multiple luns from
different RAID groups, but they are all put together behind one
directory.  Is this going to become a problem as they add more and more
load to this instance?  If TSM has lots of separate directories and they
are across multiple luns, does TSM do it's database I/O differently?

Best Regards,

John D. Schneider
The Computer Coaching Community, LLC
Cell: (314) 750-8721



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