Hi,
        Here is what I have found to be "FACT" from M.S. They do not supp=
ort
Brick Level layer backup, simply because ALL 3rd party vendor's DO NOT us=
e
M.S.'s MAPI for the brick's. They all use their own version as a gentlema=
n
stated in past e-mails. However, They "Do" support "ONLINE" backups with =
any
3rd party vendors software. WHY? because they all use M.S.'s MAPI to do i=
t.

        So this only leaves us to backup up PST files, and do restore-
import - copy over (or copy up) to existing user mail box.

So, to answer your question:  Since you can not do Brick level
backup/restores, you should at least backup the PST files. and no, you do
not have to restore the entire Info Store.  Now TSM says to do an "entire
duplicate Exchange server build" in order to recover your mail.

Here is what M.S. has suggested. Schedule CMD files with the "AT command =
(or
WinAT)" to use EXmerge utility (Exchange resource kit). Export them to a =
PST
file, import them into a personal folder and copy up the data needed. Now
you can get as fancy as you want with the CMD files and piping them to a =
TXT
file for Exmerge and what it is doing (makes for a good Exchange Admin lo=
g).

Keep in mind though. Not only do you need enough H.D.D. space for the
offline defrags but you also need to have enough H.D.D. space for the PST
files. How much? Well if your database is 4 gb? then you need at least th=
at
amount to run defrag plus (if you are using Exmerge on entire Exchange
server mailboxes) 1.5(x's) the space for the exported PST's. All together
(doing the math), using the 4gb base #, you will need 10gb of free space,=
 in
order to do all this. Yes, also keep in mind  that the PST files can be k=
ept
elsewhere AND your Exmerge can be done elsewhere as well as the PST's can=
 be
placed on other machine's. If you read up on Exmerge you will know what I=
 am
speaking of.

Hope this helps.
Tony