My initial re-action is that... that seems like a lot of hardware for 400 backup clients.
We never really specify kit based on client count - unless you get into the tens of thousands of clients at which point other issues come in to play.
Anyway, so, normally... on what appears to be a small to low-mid-sized solution... one would expect it to be sized on RPO/RTO and volume plus type of data.
And a SYM5330 is a very capable media server - are you sure you need one of those?
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And, I agree with Marianne, when one spends that kind of money, one would expect a very detailed design to have ben done, and the very nature of the design doc should naturally and smoothly lead to the writing/creation of a build and implementation document.
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I'm very sorry, but... do you see how this is one of those questions which can never be answered from a two line source question. It's such a trap. The only correct thing to do, is to give you a two line answer...
1) Install the hardware
2) Install the software
...and that's about it.
