well...
v Improve the speed with which TSM restores file systems containing many
small files.
v Conserve resource on the server during backups since only one entry is
required for the image.
v Provide a point-in-time picture of your file system which may be useful if
your enterprise needs to recall that information.
v Provide a snapshot of your file system.
v Restore a file system or raw logical volume that has been corrupted. Data
will be restored to the same state it was when the last logical volume
backup was performed.
OK, that's a little low to quote the manual...
RAW logical volumes is a real biggie... before you just couldn't do that...
say you have a DB that uses raw volumes and you wanted to take a cold
backup... you really couldn't shut down the db and backup the raw volumes,
now you can.

OK, we had a file system with 3/4 of a million files that were each less
than 80 bytes in length (on avg, so around 60 MB) and folks wondered why it
was taking an extreamly long period of time to back it up (hours)... well,
it was simply all the DB overhead associated with 3/4 million files... now
that would be a single file, as far as db activity goes and would back up in
a time you would expect 60 MB to back up in.

Now the point in time you are talking about and the point in time they are
talking about are two different point-in-time situations here...
your pit restore would replace any individual files (a subset of the file
system)
the pit they are talking about here would be a complete replace of every
file because it is/was backed up as just one large file (not a whole bunch
of individual ones) so same results, just differs by the amount of internal
tsm DB overhead and the amount of info moved.

hope this helps
later,
Dwight
> ----------
> From:         Jason Morgan -
> Finance[SMTP:Jason.Morgan AT blaenau-gwent.gov DOT uk]
> Reply To:     ADSM: Dist Stor Manager
> Sent:         Friday, August 25, 2000 6:24 AM
> To:   ADSM-L AT VM.MARIST DOT EDU
> Subject:      Backing up logical.
>
> Our site is going to be installing TSM 3.7 for AIX. We are currently ADSM
> 3.1.2.50 for AIX.
>
> On reading the TSM manuals, there is a function to backup and restore
> logical volumes via TSM 3.7 clients.
>
>
> Currently to backup a filesystem we use e.g inc /first/export and are able
> to use point-in-time restore.
>
> What benefits can the backup image and restore image functions give me.
>
> I can't see any at the moment. Can anyone enlighten me ?
>
>
> Jason
>
>
> Jason Morgan
> Technical Support Analyst
> Blaenau Gwent C.B.C
>
> Telephone: 01495 355230
> Email: Jason.Morgan AT blaenau-gwent.gov DOT uk
>