Mark,

We've been discussing this internally amongst ourselves, and the client
and server books are definitely out of sync. We will look into getting
them corrected, and updating this forum with the final answer.

Just to clarify a couple of points:

- When incremental-by-date is used to back up a file system, the last
backup date for the file space IS updated.

- In an earlier post on this thread, you said, "All PIT restores a
relative to the previous LID, i.e. if the LID is 8/8/02 4:00 and you do a
PIT restore specifying a pitdate and pittime of 8/8/02 8:00 it will roll
back to the previous LID of 8/8/02 4:00." I'm not sure I really understand
what you are getting at. When doing a point-in-time restore, if a backup
version meets the point-in-time criteria, then it will be restored
regardless of what method was used to back it up. PIT restore keys off the
date/time the backup version was created, not when the file system was
backed up. So if the LID was 08/08/2002 04:00, but at 06:00 someone
subsequently backed up some additional files, then a PIT restore using
date/time criteria of, say, 08/08/2002 07:00 would restore the backup
versions created at 06:00. The volume's LID isn't really relevant.

Regards,

Andy

Andy Raibeck
IBM Software Group
Tivoli Storage Manager Client Development
Internal Notes e-mail: Andrew Raibeck/Tucson/IBM@IBMUS
Internet e-mail: storman AT us.eyebm DOT com (change eye to i to reply)

The only dumb question is the one that goes unasked.
The command line is your friend.
"Good enough" is the enemy of excellence.




"Mark D. Rodriguez" <mark AT MDRCONSULT DOT COM>
Sent by: "ADSM: Dist Stor Manager" <ADSM-L AT VM.MARIST DOT EDU>
08/12/2002 15:15
Please respond to "ADSM: Dist Stor Manager"


        To:     ADSM-L AT VM.MARIST DOT EDU
        cc:
        Subject:        Re: Incremental Backup (full/partial)



  Alex,

I have read through your response and I can understand your position.
 However, firat I would like to point out that the TSM documentation is
not always clear and is not always consistant.  The text you quoted from
the Admin Guide is an example of them not being consistant.  Clearly
what they are describing there is a "incremental -incrbydate" type
backup.  And as I stated earlier you can consider it a "partial
incremental", but that does not mean that a "partial incremental is only
acheived by "incremental -incrbydate", that's like saying "I live in
Texas therefore I am a Texan and an American" based on that fact I can
say all Texan's are Americans, but not all Americans are Texans.

I will concede that there is places within the documentation that refers
to the "-incrbydate" option as beeing a "partial backup" and I can show
you IBM/Tivoli education material that describes a partial exactly as I
did in my note.  But rather than nit picking the symantics I would like
to re-phrase my explanation,  Instead of calling it "full incremental"
and "partial incremental" maybe we should use full and non-full.  The
key here is what happens when you don't use "full incrementals", in
particular the Last Incremental Date ( what I refer to as the LID) does
not get updated.  This is a critical peice of information.  Much of the
documentations explanation for other processes are assumming that you
are doing fulls since it keys off of the LID.  In addition, what other
processing is being effected by your "non-full incremental" (filespec
limited or -incrbydate option), i.e. file expiration, rebinding, missed
files etc.

The point that I am really trying to make is you should always be doing
full incremental backups!  The only time to consider anything else is if
there is a severe time constraint on the backup window.

I think this thread has been great.  It has given people a look at how,
what and why TSM is doing what it does.



--
Regards,
Mark D. Rodriguez
President MDR Consulting, Inc.

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