We have extensively tested Plastic on EC2, in fact it is one of the main environments where we run Plastic SCM tests.
It all depends on the load that the server needs to handle.
Tiny server for occasional pushing and pulling
For instance, the demo server we use to handle the evaluation guide runs on a tiny EC2 instance, with Linux and MySQL and a total RAM of 512Mb. It is good for occasional pushing and pulling but of course not to be used under heavy load.
Big server for extreme load
On the other hand, we use a more powerful server to run 'load tests' with 300 concurrent bot clients doing about 2000 checkins per minute on a big repository. We detail the specs here. Basically, for higher perf:
- 20GB RAM
- 2 x Intel Xeon X5570
- 4 core per processor (2 threads per core) (2.7Ghz) – 16 logical cores – Amazon server running Windows Server 2012 + SQL Server 2012
Central vs distributed development
That being said, remember that if you setup a cloud server your bigger restriction for heavy load won't be the server itself but the network. If you plan to work in a centralized way (your workspaces directly work connected to the cloud server) then network will definitely be a consideration. Every checkin, every create branch, every switch to a new branch will mean connecting to the remote server and chances are that you won't get the same network speed you get on a LAN.
The other option is that you work distributed: you have your own Plastic repositories on the developer machines and you just push/pull to the central server. If that's the case it will work great and the requirements won't be high at all.
Specs for a 15-users team working distributed + Amazon EC2 server
If that's your case I'd go for:
Hope it helps :-)