Ahh, Minecraft .
I run a server at home for my two kids (and me if I get the time) and have now opened it up to a few of my older sons friends. It does not get heavily loaded but there are a few things to watch out for.
You really need to work out how many users you are looking to host per server in order to calculate the amount of ram and disk space you will need. Without that information it is very hard to work out resource requirements and offer suggestions which will do for now but give scope to upgrade if your requirements change in the future.
A few points to remember hardware wise;
- Servers do not require decent video cards in order to host Minecraft. A motherboard or processor video chipset will do fine.
- Ram is good, more ram is better (within reason).
- You will want fast disk (higher IOPS the better) for Minecraft as it writes to disk often as the world changes.
Intel 520 series of SSDs would be a good choice.
- Minecraft does not take a lot of CPU power per user.
- Minecraft does not take a lot of disk space.
- Consider running your Minecraft servers in virtual machines on a single set of hardware
As long as you have fast storage, other resource requirements fro Minecraft are pretty low.
I would suggest building a virtulization server (VMWare vSphere 5.0 or 5.1 when released on Sept 11th) based on;
- Intel S1200BTLR server motherboard
- Intel E3-1230 v2 Processor
- Kingston KVR13E9K2/16I 16GB ECC ram (2x 8GB gives you 2 slots free for future upgrades).
- Intel AXXRMS2LL040 4 port SATA III controller module (to connect 4 SSDs at full speed).
- 4x Intel 60GB 520 SSD (one for each Minecraft instance is best but all 4 on one SSD would not be too bad depending on expect user volumes).
- Seagate Barracuda 2TB hard drive for storing the worlds backup snapshots so you can restore if corruption occurs (WD RED 2TB / Hitachi 2TB or any other brands also good).
- USB stick for vSphere boot drive.
That comes to just over US$1,200 (shopping around should get you cheaper). Drop to 8GB if you really need to cut down further.
For the chassis, you have not said what type of case you want (rack or pedestal / tower). If you go rack mount then just be aware that the S1200BTL/BTS boards do not go well with other makers 1U chassis. Either get a bigger rack mount chassis or a tower / pedestal case. The S1200BTLR is an ATX board so you need to take that in to account.