ADSM-L

Re: [ADSM-L] using dsmc to retrieving large number files

2009-05-22 06:36:10
Subject: Re: [ADSM-L] using dsmc to retrieving large number files
From: Dwight Cook <cookde AT COX DOT NET>
To: ADSM-L AT VM.MARIST DOT EDU
Date: Fri, 22 May 2009 05:35:07 -0500
I've noticed in 5.5.1 server (healthy AIX server running virtual tape
library so minimal mount delay, etc...) with 5.4.2 windows clients that if
you are performing a restore where over 1.5M files exist within TSM for a
single drive, it can take 7-10 days to perform the restore.  If you have
2.5+Million files, give it 3-6 weeks.  Seems to partially be due to the
internal locks within the TSM server's data base associated with things such
as expiration, reclamation, etc... (this is with a TSM DB of roughly 200 GB)
However, this is why there are things like IMAGE backup. To speed up backups
and restores when millions of files exist in a single file space.
AGAIN... just because you CAN put a few million files under a single mount
point doesn't mean it's a good idea to...

-----Original Message-----
From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU] On Behalf Of
Richard Sims
Sent: Thursday, May 21, 2009 6:38 PM
To: ADSM-L AT VM.MARIST DOT EDU
Subject: Re: [ADSM-L] using dsmc to retrieving large number files

In the absence of details, the List membership can only postulate what
factors may be at play...anything from tape seek delays to network
routing.  You'll have to assess the Archive vs. Retrieve statistics
and server Activity Log entries in conjunction with your knowledge of
the configuration there to gain more perspective on all contributing
factors.  One thing that's certain is that there's more overhead in
creating new files than in reading existing files - worse in some
operating systems than in others.  And, realize that MAXNUMMP is in
play at Archive time, but not Retrieve time.

     Richard Sims