I made something like this myself a while ago, albeit much simpler, for some crazy project. Generated a couple of CDs of data in not very long - the RS232 link was the bootleneck.
A couple of good links for those that want to give it a try:
I lost track of the actual links that I used but it's all roughly the same principle. One of the links I lost track of had a paper describing how random avalanche noise is, had some favourable things to say.
If you want the real thing, get a beam splitter. I'm not naming names or really saying anything credible at all, but electronic noise isn't in the same ballpark.
Possibly. If your SSH and HTTP daemons and encrypted file systems use /dev/random, and you're running Linux, then possibly. Look in /proc/sys/kernel/random/entropy_avail, and possibly graph this over time. Also, some modern Linux distributions use data from the random pool at exec() (to randomise linkage), and so it's possible you could be running low already. TLS email also consumes huge amounts, and anybody running virtual servers might be having a problem.
Is there anyway to speed this up without hardware? My server has a laughably low amount of entropy available and I think it is why a lot of the connections are slow.
If not what is a cheapish way to get hardware entropy?
If you have a sound chip on your server which is capable of disconnecting itself from the microphone socket on the back then you might be able to use low-order bits from that and a tool such as the audio entropy daemon or 'randomsound' (the latter is packaged in Debian) however I'd not recommend that as anything other than a stopgap until you can get something more effective.
Simtec expect to release their Entropy Key for around GBP42 delivered in the UK. (worldwide postage costs will obviously inflate that a bit).
Looks like it may be available by my birthday in a few months, maybe I'll suggest it if someone asks what to get me as a gift.