Hi folks,

last week we experienced some strange things happening on our ADSM-Client
System. We have a rather large AIX 4.1.4 System with about 300GB SSA
Disks, this system serves as a fileserver for a supercomputer, HSM is
enabled for all user filesystems.

Last week some users decided to change permissions on a very large amount
of already backuped files ( ~ 25 GB ). This caused the scheduled backup to
backup every single file of that user. According to the Administrator's
Reference V2, any file is considered changed, when any of the following is
changed:

        o date last modified is changed
        o file size is different
        o the owner is different
        o the permissions are different

when Mode=Modified is set on the copygroup.

The first two are ok, but the last two affect IMHO only the inode, and not
the data, so the change/update should be made to the database only.

This caused a major amount of files to be backed up almost unnessecary,
adding to our normal amount of daily 2-3GB Data backed up. The performance
we gain from our ADSM Server is about 0.3 GB/h, so this will take about 4
days. How could we increase this performance?

A malicious user might have a job that change the permissions every other
day. Also a "good" user may change the permissions for his files, and this
might cause major performance and service loss.

What happens to files which are already migrated, because chmod does not
recall the data, and dsmc schedule might fail to recall the file during
the backup process. At least I observed this behaviour some weeks ago.

Any other member of this list who has experienced this as a problem?

Is this a bug or a feature?
well, its documented, so it needs to be a feature :-(


        Andreas


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|       Andreas Landhaeusser                                           |
|       Deutsche Forschungsanstalt fuer Luft- und Raumfahrt e.V. (DLR) |
|       Bunsenstr. 10                                                  |
|       D-37073 Goettingen                                             |
|       Germany                                                        |
|       Phone: +49 551 7092379  EMail: Andreas.Landhaeusser AT DLR DOT De     |
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