bitcoind stops working
I had a similar problem - it turned out that Bitcoin was running out of memory. (This happened when I was using one of DigitalOcean's 512MB VPS's.)

Here's what you can do to check if this is the problem:


Run the command watch free -m

You'll see something like this:

             total       used       free     shared    buffers     cached  
Mem:           997        891        106          0        117        640
-/+ buffers/cache:        133        864
Swap:         4095          0       4095

Look at the intersection of -/+ buffers/cache and free. This is how much free memory you have. In this example, it's 864 MB.
If that number drops below 10 MB before the crash, that's probably the issue.


Here's what you can do if this is the problem you're having:


Get a larger VPS from your provider.
Enable swap
Try adding

dbcache=50
maxconnections=4
rpcthreads=2


to your bitcoin.conf file.