I really haven't seen a sliding scale graph or chart of average hardware requirements per 25, 100, 250, 500, 1000, 5000, etc. users. Does anything like that exist?
I'm on the path to creating a small email service for my clients and intend to continue selling it and make it as big as possible. The main concern for me is speed for clients and reliability.
I have plans to pick up some pretty redundant hardware for my servers, and I know that anything can go wrong with a single unit, so if one intends to get into this business, they better have something that can take over in the event of a failure of the main units. So, that being said, is something like the Red Hat clustering solution indicated as a barest necessity as far as high-availability goes? Any recommendations? Or, is it possible to just have a server on standby and watch the main one like a hawk? Or can a shared storage be used and active-passive server relationship be used?
As for storage, I am not sure how to proceed. I suspect that some simple RAID 1 storage will work for the mailboxes and databases and when I max-out the capabilities, I'll have enough cash in the door to drop the cash on a solid storage solution.
Not even sure how much CPU power I'm going to need to push this service.
Any help would be appreciated.