[Veritas-bu] NDMP Incremental Problems

The mystery has been solved, thanks to technical support from both Network
Appliance and Veritas.

For those of you who aren't up on this, here's the scoop:

   * Running NetBackup/NDMP for backups on a CIFS only Network Appliance.
   * "Differential Incremental" backups, a.k.a. Daily backups, were backing
up ~20% of the data every night. BAD!
   * Bug report (177767) didn't apply, since we're running ONTAP 6.01R, and
that bug was fixed in that version.

The solution - an "undocumented" new feature for NDMP, which tells NDMP to
ignore the ctime on files when doing Incrementals. We went from >254
Gb/night to just over 70 Gb/night. This is a SIGNIFICANT improvement, which
will save our company a lot of money, and ME a lot of headaches! Many sloppy
WIN32 applications, including McAfee virus scan, touch the ctime when they
open a file.

To fix, type "ndmpd ignore_ctime " from the command line on your CIFS only
NetApp. This is a toggle, which will set this parameter to true. Run it
again, and you've just shut it off again!

*********** If you are running a CIFS only filer, and are using NDMP to back
it up - CHECK YOUR INCREMENTAL BACKUPS! If they seem large, try this setting
and note any changes. This is NOT specific to Veritas - it is an NDMP issue,
so Legato or Budtool backups could be affected as well.

Good luck!

Kim