I have been looking at the same question: When is an ADSM server full, =
and
when do I need to order a new one to cope with the extra clients that =
needs
to be backed up to it?

These are some of the things that affect that choice:-


The capacity of an ADSM Server can be measured in a number of ways. The
actual maximum capacity is a combination of all of these measurements:

=B7 Off-Site Tapes. The main purpose of the ADSM environment is to =
allow
restores of the IT systems in the case of a disaster recovery =
invocation.
Therefore, it is important that no more off-site tapes are produced =
than can
fit into the DLT tape library at the same time.

=B7 On-Site Tape Space. As well as allowing off-site recovery, ADSM =
also
stores copies of the data it has backed up on on-site tapes. The number =
of
tapes in use for this purpose must be less than the capacity of the =
library,
and still allow enough slots to handle the daily off-site tapes that =
are
produced.

=B7 Disk Cache. When overnight backups take place, the files are first =
copied
to a disk cache on the ADSM server. This disk cache must be capable of
holding all files modified and backed up each day.

=B7 CPU Power. The system must have enough CPU capacity available to =
allow the
ADSM processing and database manipulation to take place.

=B7 Database space. The ADSM system must store information about every =
file
that is backed up. This information is stored in the ADSM database. IBM =
have
in the past recommended that this database does not grow to more than =
20
GBytes.=20

=B7 Overnight backup window. Client systems are backed up each night. =
The
systems must be able to backup their modified files within the backup
window, which is approximately 18:00 to 03:00. As more systems are =
added to
the environment, the intervention between systems causes all processes =
to
slow down, and can therefore no longer be backed up within the desired =
time.

=B7 Daily processing. Once the overnight backups from client systems =
are
complete, the ADSM server must perform its daily processing. This =
involves
copying data to off-site tapes, backing up the ADSM database, moving
required start up files to a floppy disk, operators moving tapes into =
and
out of the ADSM server to and from the fire safe, expiring old data,
migrating information to on-site tapes, merging half used tapes =
together.
This processing must be completed before the next nights backups start.

A new ADSM Server will need to be purchased and implemented before any
individual factor detailed above exceeds the limits or time available.


Cheers,=20

Chris Jordan
CMG UK Ltd.