you are having I/O errors on /dev/sdh.
Those are filling the syslog to where you are running out of available memory, so the out-of-memory process in the kernel is killing off processes in an attempt to free some memory. (and killing off your login shell, the pre-clear process, and probably your screen session too)
And apparently my webGUI as well if it goes long enough. I got home, hooked up my server to a monitor to see what was going on since my telnet is down, and sure enough, that error is stilllllllll going. I'm currently trying to get my web back up, so I can shut things down since my powderdown script doesn't even seem to want to work.
I did noticed the I/O errors in the logs, did some various searching around on the forum, but I wasn't entirely sure what to do next in order to get things fixed. I'm still searching around google and the forum to see what exactly my next steps should be. I'm assuming double check cables? (My understanding is I/O errors could mean many of things, or I'm terribly wrong in that guess.)