I agree with Chris on this one - 100GB!! Yikes.

For starters if you want to maintain this sort of Info Store you'll need at
least a 200Gb Disk Array (double the disk space in order to defrag the db)
I don't know what you're SLO's are for recovery but if you wanted to I
reckon you'll be doing a full backup every other day.

The incrementals for a store of this size are likely to be about at least
7Gb per day (we average 2-3Gb on a 30Gb store). If you had only to restore
one full backup and then one incremental (7 Gig of log files), even if you
had a speed demon of a server (4 or more 600Mhz processors) you're talking
at least 9-10hours to play back 7Gb worth of log files and if you're server
is only a dual processor then you could be waiting a lot longer. On top of
that it would take at least 15hrs to restore a 100Gb store with a 7Gb
incremental (and that's with a fast network). Total time for recovery would
therefore be in excess of 24hrs.

Most companies now consider email to be a business critical application.
Consolidating multiple exchange servers may save some money on the initial
hardware outlay, but the bigger they are, the harder they fall as more users
are impacted for possibly greater lengths of time. In order to maintain
availability on a store of this size, i'd be looking into clustering the
exchange server and I'd perhaps consider looking into EMC's timefinder for
BR - both very expensive options.

Nathan






        -----Original Message-----
        From:   Jordan, Chris (ELS) [SMTP:c.jordan AT ELSEVIER.CO DOT UK]
        Sent:   Thursday, October 21, 1999 3:08 AM
        To:     ADSM-L AT VM.MARIST DOT EDU
        Subject:        Re: ADSM and Exchange

        100 GB per server - not us. 100 GB over 3 servers - Yes.

        Exchange can certainly cope with servers that large, but you need to
        consider carefully your restore speed. Restoring a database of this
size
        will take a minimum of 4 hours - and quite probably longer. Before
you can
        restore the data base you have to re-build the system, NT and
Exchange.
        After the restore you need to check the system carefully. That would
be (a
        conservative estimate) 8 hours down time.
        Exchange doesn't go down very often, but when it does it becomes
critical
        fairly quickly.
        It is not just the database restore time. Also the log files that
need to be
        replayed after a system crash and re-start, or the database analysis
tools,
        take time (measured in hours, not minutes) to run.

        We decided on smaller servers just because of this restore time
problem.
        Real life? Out of the 35 servers only one has needed restoring after
12
        months of use.

        Whether you use ADSM or a different backup mechanism does not make
much
        difference.

        Cheers, Chris

        -----Original Message-----
        From: Joel Cooper [mailto:jocooper AT DTTUS DOT COM]
        Sent: 20 October 1999 22:59
        To: ADSM-L AT VM.MARIST DOT EDU
        Subject: ADSM and Exchange


        We are soon to move over to Exchange for mail and, with over 21,000
users,
        we
        expect huge DB sizes.

        Is anyone out there backing up Exchange with ADSM to the tune of
over 100GB?
        Your input would be greatly appreciated.

        Thanks,

        Joel Cooper
        Deloitte & Touche LLP
        jocooper AT dttus DOT com