Re: Does TSM check AIX permissions?

While that's what the book says, it's not what appears to happen.  I
tested this on AIX 4.3.3 with a 4.1 client and a 4.1 server, and on
Solaris 7 with a 3.7 client and a 3.7 server: the file is not backed up
again.

Changing the permissions on a file doesn't alter the file - it alters
the inode, so it's the ctime (originally the "creation" time, now
"change" time) that's changed, while TSM checks the mtime
("modification" time) when determining which files have changed and need
to be backed up.
Any change to a "file" that only updates the inode (i.e. ctime is
changed but mtime is not) results in the client updating the TSM DB
entry, but not backing up the file; any changes to the contents of the
file change mtime, resulting in a file backup.  chmod, chgrp, chown
change ctime while leaving mtime alone.

However, if you're using ACLs on AIX, modifying the ACL does cause a
backup of the file.  Normal Unix permissions fit within the file entry
in the TSM database so only an update is needed to store the new
permissions. ACLs have the potential to be too large to fit in the DB
entry, so they're stored with the file; when the ACL is changed the file
is backed up again.

Here's the trimmed down output from a test:

% echo foo > testfile
% ls -l testfile
-rw-r--r--   1 swl      staff          4 May 25 10:40 testfile
% dsmc incr testfile
% dsmc incr testfile
Total number of objects inspected:        2
Total number of objects backed up:        2
Total number of objects updated:          0
Total number of bytes transferred:       39

% chmod 777 testfile
% ls -l testfile
-rwxrwxrwx   1 swl      staff          4 May 25 10:40 testfile
% dsmc incr testfile
% dsmc incr testfile
Total number of objects inspected:        1
Total number of objects backed up:        0
Total number of objects updated:          1
Total number of bytes transferred:        0

% dsmc q backup testfile -ina
             Size      Backup Date        Mgmt Class A/I File
             ----      -----------        ---------- --- ----
                4  05/25/01   10:41:16    DEFAULT     A
/home/swl/testfile

% rm testfile
% ls -l testfile
testfile not found

% dsmc restore testfile
Total number of objects restored:         1
Total number of objects failed:           0
Total number of bytes transferred:       39

% ls -l testfile
-rwxrwxrwx   1 swl      staff          4 May 25 10:40 testfile
--
--
Scotty Logan <swl AT stanford DOT edu>
Scotty Logan <swl AT stanford DOT edu>
ITSS-CSS http://www.stanford.edu/group/itss/css/

> -----Original Message-----
> From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU]On
> Behalf Of
> Richard Sims
> Sent: Friday, May 25, 2001 10:12
> To: ADSM-L AT VM.MARIST DOT EDU
> Subject: Re: Does TSM check AIX permissions?
>
>
> >Should TSM consider the change of AIX permissions to be a
> modification of
> >the file, and therefore, back it up.
>
> Yes.  See the B/A Client manual, "Backing Up and Restoring
> Files" chapter,
> "Backup: Related Topics", "What Does TSM Consider a Changed File".
>
>   Richard Sims, BU
>