Here is the situation: I am running CentOS 5.7 x86_64 with Xen 3.0.3 (xen-3.0.3-132.el5_7.2.x86_64) and the Xen kernel (2.6.18-274.12.1.el5xen). The server has 8GB RAM, and an i7-950 @ 3.07Ghz. I am using it to host two guests - Windows Server 2008 R2 and CentOS 6.2 x86_64 - both using full-virtualization and LVM partitions.
For the last week or so, this server has been crashing 5-10 times a day, sometimes mere minutes after the last boot. Nothing about the machine has been changed, and no new software has been installed (I've been using this kernel/Xen version for about 3-4 weeks before with no problems).
The machine is running perfectly, then just stops - nothing on the console, nothing (that I can see) in the logs. It has to be rebooted by powering down then up again, and sometimes it will happen again within just a few minutes. A full hardware check was run a little over a week ago, and everything came back clean. Using e2fsck did fix a couple of issues, but hasn't actually resolved the situation (if anything, it now seems to crash more regularly).
When I was booted into a live CD last night to run the e2fsck, it ran fine for ~8 hours without any crashes (which it probably wouldn't do under the CentOS install on the drive). It sounds more and more like a software issue, but it's difficult to pin down, seeing as no configurations have been changed, and no new software has been installed.
I've checked all the system logs, and nothing seems out of place. I've also done a full check of each partition using e2fsck. I've linked the pastebinned logs below, but I just can't figure it out.
Any help on this would be much appreciated. Thanks in advance.