I like to tell our users that  TSM updates it's current "full backup" image
with every incremental.  TSM doesn't need to move all the files every time,
and it makes no sense to do that.
(Except in the event of creating a full backup image on as few tapes as
possible for a quick restore)



                      "Seay, Paul"
                      <seay_pd@NAPTHEO         To:      ADSM-L AT VM.MARIST DOT 
EDU
                      N.COM>                   cc:
                      Sent by: "ADSM:          Subject: Re: Incremental & full 
backups
                      Dist Stor
                      Manager"
                      <[email protected]
                      T.EDU>


                      05/22/2002 08:33
                      PM
                      Please respond
                      to "ADSM: Dist
                      Stor Manager"







J-B,
The best description of TSM is that it is a full backup that is
incrementally updated each time you run a backup.  You can force a full
backup by using a mode=absolute in the management class copy group when
ever
you want to re-backup everthing regardless.  The other alternatives are
backupsets and the selective command.  However, the key is understanding
TSM
is a storage management tool that does backups and recoveries as needed.
It
is not just a backup tool.  TSM's philosophy has a business data retention
orientation.  If you have paper documents you don't just keep every 7th
revision to it, you keep them all until they have reached an expireation
based on length of time or number of back revisions.  TSM does exactly
that.

The issue is the "incremental forever" misnomer that TSM gets.  First of
all, it is not incremental in the sense of any other backup product.
Secondly, it is not forever, it is based on your policies for reclaimation
and other techniques you can use.

Read some of my other responses on this subject at www.adsm.org.

Paul D. Seay, Jr.
Technical Specialist
Naptheon, INC
757-688-8180