This time something is killing both my nginx and monit processes. Could it be a memory issue when the server spikes here is my free-m
process printout
total used free shared buffers cached
Mem: 747 452 294 0 9 92
-/+ buffers/cache: 350 397
Swap: 255 1 254

do I need to upgrade?

please let me know if there are any other commands that I should run to print out here. I don't think it is a networking issue. I think this
happens when googlebot visits my sites but not absolutely sure. Any help would be appreciated.

According to your free output, you've got 397 MB of free memory.

When the killing of nginx and monit is going on, you could keep an eye on the output of 'top' to see if anything strange is going on. Also, check your nginx, monit and system logs.

So what's in the system logs under /var/log ?

What's in the kernel log ( dmesg ) ?