[Veritas-bu] What criteria is used to determine a incremental ??

It uses mtime by default:

from the SAG for v5.1 pp 152-153:

When NetBackup reads the data for a file that is included in a backup, it
does not affect the file modification time, but does affect the access time
of the file. For this reason, NetBackup saves the atime and mtime of the
file prior to reading the file, and (by default) resets the atime and mtime
using the utime(2) system call. By doing it this way, NetBackup does not
cause problems for storage migration products or administrator scripts that
are utilizing file access times (atime) as criteria for their operations.
While this benefit is obvious, a side effect is that it does update the
ctime of the file.

As an option to a NetBackup configuration, customers can choose to have
NetBackup not reset the access time of the file after it reads a file.
Additionally, customers can choose to have NetBackup use the ctime of the
file, in addition to the mtime, when determining what files to back up in an
incremental. Normally, these two options are used together, but there may be
sites which want to use one without the other. By default, NetBackup uses
only the mtime of the file to determine what files and directories to back
up.

When a file is moved from one location to another, the ctime of the file
changes, but the mtime remains unchanged. If NetBackup is only using the
file modification time (mtime) to determine files due to be backed up during
an incremental backup, it will not detect these moved files. For sites where
this is an issue, the ctime should also be used (if possible) to determine
files due to be included in an incremental backup, using the bp.conf
attributes USE_CTIME_FOR_INCREMENTALS and DO_NOT_RESET_FILE_ACCESS_TIME.

When a directory is moved from one location to another, the ctime of the
directory changes, but the mtime remains unchanged. Neither the mtime nor
the ctime are changed for the files or directories within the moved
directory. Using file timestamps, there is no reliable method for
determining that files within a moved directory need to be included in an
incremental backup.

In either case, these moved files and directories are included in subsequent
full backups.

-----Original Message-----
From: Donaldson, Mark - Broomfield, CO 
Sent: Wednesday, November 02, 2005 9:44 AM
To: 'sander AT humilis DOT net'; Donaldson, Mark - Broomfield, CO
Cc: Steve.Bally AT radisys DOT com; veritas-bu AT mailman.eng.auburn DOT edu
Subject: RE: [Veritas-bu] What criteria is used to determine a
incremental ??


I'll see if I can verify but I think this is right. I don't think NB is
sensitive to simple permissions/ownership changes.

Time to play with my test policy.

-M

-----Original Message-----
From: Sander [mailto:sander AT humilis DOT net]
Sent: Wednesday, November 02, 2005 1:23 AM
To: Mark.Donaldson AT cexp DOT com
Cc: Steve.Bally AT radisys DOT com; veritas-bu AT mailman.eng.auburn DOT edu
Subject: Re: [Veritas-bu] What criteria is used to determine a
incremental ??


Mark.Donaldson AT cexp DOT com wrote (ao):
>    For Unix, it's by timestamp (mtime value on the inode).

Should this not be ctime? In my experience (Linux) mtime only changes on
a change of the file (eg, data), while ctime also changes when the
rights or owner change.

        Kind regards, Sander Hollaar

-- 
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