The tool suggest 12 HP servers with 20 TB of storage. Since High
Availability (HA) in case of Exchange means an active-passive setup, you
buy 6 servers that don't do anything as long as the other 6 don't fail
(HP builds great machines, so the probability is rather low). The 12
servers do not include the setup for Microsoft Active Directory which
would add at least 2 more boxes (one could argue the directory is needed
in any case - which I happily would debate, but that's a topic for
another day). The whole setup looks like this:
Now let us compare this to a Domino setup on an IBM System P. On a
System p550 (that's not even the latest IBM P7 system) you would choose
to run 3 LPAR (Logical partitions) with a total of 5 Domino partitions
(4 for user access, 1 for directory and hub). Since Domino is an
active-active cluster you have 6000 users per server or 1500 users per
Domino partition (which is calculated on the super-save side. I've seen
production systems with 10k and more users on one partition - but we
have heavy users here). The whole setup looks like:
What is not in the picture are considerations around storage. IBM claims
that the same amount of eMails on a Domino system needs substantial
less storage than on Exchange, but that calculation is up to you (keep
in mind how to configure
a high performance server). Lesson to be learned: always ask any vendor to list out the machines they will need. More to come.
) suggest to base management decisions on 
.
So what is part of TCO? Hardware and software prices, real estate in
the server room, electricity and cooling, labour for the admin for
regular operations, patches and upgrade as well as opportunity cost for
downtime. I'd like to shed some light on the hardware side. In a loose
series will compare the hardware deployment for various IBM and
Microsoft scenarios. For starters I use a comparison of plain Domino
with plain Exchange.