Crash Logging

[ArchBeekeeper]

Hey all! This is my first post, so if it belongs somewhere else, please let me know. I have a Raspberry Pi running Arch Linux ARM. It's headless, and I don't even have a monitor to hook it up to. I log into it via ssh on my netbook. It crashes periodically, where all the lights are on and blinking, but it "crashes" and goes offline (no ssh login). It's connected to the router by and ethernet cable, and when it "crashes" the router no longer shows it as a listed device. I think more than likely it's due to running too many programs at once, but I'd like to know what's going on.

My main question is this:

What do I need to do to create a log to find out what is causing the problem? I've read the Wiki on the subject, but any advice from someone with more knowledge would be greatly appreciated. In return, I'd be more than happy to answer any questions about beekeeping or beer brewing (I've been doing both for over a decade each). Thanks in advance.

[pepedog]

It really isn't typical these things crash.
Things that can let it down is rubbish power supply, some sd cards, and current draw on usb.
If you have a lot of things running then a swap file will help, but make sure it's on a spinning hard drive https://wiki.archlinux.org/index.php/Swap#Swap_file_creation. If you go down that route, make it ext3, copy data on second sd card partition to it, and edit /boot/cmdline.txt to reflect rootfs is on /dev/sda1 and its ext3
Things will buzz nicely then

[rpisays42]

I just noticed a very similiar behaviour (Pi not ssh-/pingable). I had connected an USB DVB-S2 card to it. It only seems to "crash" if its in idle for a longer time, because it streamed tv almost all day without problems.
Maybe its some software bug, maybe there's some hidden idle/sleep mode we aren't aware of, or the good old psu problems. Tonight I will try disconnecting usb devices and turning of the tv streaming server (tvheadened). If its still on when I wake up it might have something to do with that ...

[ArchBeekeeper]

I figured out the problem with mine. I posted a solution here:

viewtopic.php?f=31&t=4636