Dumb question, but what exactly is the SQL server used for?

Does each client speak to the SQL server or just the ZCM server?

What level of utilisation would be typical for say 1,000 users?

How well would this scale up to say 18,000 users?

In my organisation, we are looking to roll-out ZCM to 20 users initially (One department), then 300 (One location). If successful progress through 1000 to 6000 users, then onwards up to potentially about 18000 users in total.

I have currently setup MS-SQL 2005 in a two-node fail-over configuration, dedicated to ZEN-SQL.

Is the above SQL setup better or worse than than using a 3 node (initially) MS-SQL load-balancing cluster shared with an indeterminate load from other SQL-Databases in use on the system?

So many unknowns!!! Any help greatly appreciated.

Thanks in advance,
Shaun Dunmall