My Linux box, which is currently on Fedora Core 3, locks up randomly, and I'm trying to find out why. I'll be listening to a stream off of it, or accessing a page on apache, or doing nothing at all, and it will lock up. At that point I have to hold the power and boot it back up. Can someone point me to common log files that may explain why the system is locking up?

Virtually all log files will be found in directories under /var/log. You will need root privelages to see them. Chances are, you will find nothing useful there. Your system's symptoms are typical of a failing power supply. Is there any other OS installed, and if so, do you witness simlar symptoms when running those? Are you sure the whole system is dead, or is it just the X server? Can you 'Ctlr-Alt-F1' to a text console? 'Alt-Backspace' to kill the X servr process? Login remotely with ssh or other net access? There are hardware monitoring tools (sorry names escape me at this instant), but you might want to keep an eye on CPU temperature, fan speeds, etc.

--- rod.

Its a brand new Power supply. I replaced it, thinking it was that. I have a big house fan blowing on it, because I thought it could have been heat also, but its not. I have not tried Ctrl+Alt+F1 yet, I will try it the next time. One of the symptoms is that all of my connections to it freeze, they don't drop. And if I try to connect, it just sits there, it won't time out, but it will wait, until the server is shut down.

I was planning on reinstalling the OS shortly, and I am hoping that might fix it, since heat and power seem to be ok.

Sounds like you've already got the hardware side covered. I guess you could try removing services one by one and see if that changes anything. Did it always do this under the present OS, or did it start at some point after behaving well? Tried a different kernel? Video cards, especially older nVidia cards, have been a source of problems for me. Done any driver upgrades lately?

If network connections freeze, it is probably more that just an X server problem, methinks.

--- rod.

I'm really thinking its the OS. This computer started on FC1 and has since upgraded to 2 and then to 3. It was fine on 1 and 2, then on 3 for a while, but in the last few months, has started the locking up. I'm not on the latest kernel, because the last time I moved to the latest, it broke my MythTV software, not sure why. So I've been sitting on an older kernel. I do have an nvidia card, and I don't think there are any updates for the kernel I am on, but I will check.

I'm pretty much convinced it must be the OS. I think it's time for a clean install to FC5. I'll start backing up data and scripts I need, and hope that the problems disappear.

This may not be related, but I had a similar problem on a Dell server running XEN, where the server would lock up seemingly at random. We found out that you have to disable the USB on some Dell servers for XEN. I even had to disable USB on an older Dell running RH because of IRQ conflicts.

I do remember seeing a message when I was SSH'd into my box that said something about disabling IRQ10, and it locked my machine after that. I wonder how I check for IRQ conflicts in Linux.