Backup Central

All,

I have NBU 4.5 running on AIX 5.2. We have 27 filesystems sized at 200G.
The files stored within these f/s are on average 120K. That is, there is
< at > 1.8 million files within each filesystem. The backups policy is running
mpx with 4 streams going to each tape drive ( 8 LTO drives total ). The
backups are completing in about 16 hours. I think the reduction of the
filesystems to 50G ( < 500K files per f/s ) might help to improve
performance. Has anyone else experienced this degradation of performance
with many small files within a f/s, and if so, how did you resolve the
issue. Please give specifics for average file size, f/s sizing and
performance improvements.

Thanks,
Kyle

--OgqxwSJOaUobr8KG
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On Mon, Jan 24, 2005 at 05:54:54PM -0500, O'Connor, Kyle (Contractor) wrote:
I have NBU 4.5 running on AIX 5.2. We have 27 filesystems sized at 200G.
The files stored within these f/s are on average 120K. That is, there is
< at > 1.8 million files within each filesystem. The backups policy is running
mpx with 4 streams going to each tape drive ( 8 LTO drives total ). The
backups are completing in about 16 hours. I think the reduction of the
filesystems to 50G ( < 500K files per f/s ) might help to improve
performance. Has anyone else experienced this degradation of performance
with many small files within a f/s, and if so, how did you resolve the
issue. Please give specifics for average file size, f/s sizing and
performance improvements.

What filesystem are you running? You might find an improvement by using
JFS2 and tuning (per
http://publib16.boulder.ibm.com/pseries/en_US/cmds/aixcmds3/ioo.htm)

Things to look into are maxclient and maybe inode cache sizes.

You should also look at your disk back end to make sure it is layed out to
support a random access pattern (i.e. you have many small files).

HTH,
Dale

--OgqxwSJOaUobr8KG