ESXi randomly locks up

[mmiller1]

I recently purchased two identical servers and installed ESXi on them. One server works fine, the other was locking up every night.  There were no errors, it just stopped responding to all input. It would always happen overnight but not at the same time. Sometimes it would be at 7pm, others at 7am or anytime inbetween. The hardware reported a few strange things so long story short, the vender replaced the entire box.  The new box arrived last week,I  installed ESXi on it and it ran fine for 5 days. Then last night it did the same thing, it stopped responding to all input, but hasn't reported any errors.

Any ideas on what would cause this or where to start looking?

[DSTAVERT]

I would make sure you had all firmware up to current levels suitable for ESXi. I would run whatever diagnostics that came with the hardware. I would change the logging to point to a datastore or set up a syslog server since ESXi writes logs to a RAM disk and so are lost after a restart.

Syslog
http://kb.vmware.com/kb/1016621
http://kb.vmware.com/kb/1019102

[DSTAVERT]

Almost forgot.

Welcome to the Communities.

[mmiller1]

The hardware tests fine.

It looks like the syslogs are saved by default to [] /scratch/log/messages which persists after reboot. Or are there other logs that are not saved?

[mmiller1]

Firmware is also all at the latest and gratest. 

[golddiggie]

Download the memtest ISO file, burn it to a cd and run that for 24-48 hours (continuous loop) to really test out your hardware. If you can run the test for longer, I would...

I've found that to be a much better "burn-in" test of systems than anything included with the boxes. I've used it to discover memory sticks that passed manufacturer testing utilities, but failed under the load provided by memtest.