Simon Slater wrote:
G'day all, This is an inconvenience that I would like to get to the bottom of. I have a PII 233MHz 512 MbRAM running FC6. All is fine until swap reaches about 25% used then the system hangs. It will run for days with the swap at 10-15%. My first thought was to run badblocks to see if that was the problem, since it is an old drive, but couldn't find the swap device with mount.
25% of your 1 GB swap space is about 50% of your total RAM. 50% is also the default value of the vm.overcommit_ratio sysctl, which controls how optimistically the system overcommits memory. Coincidence? Maybe, maybe not.
I suggest setting vm.overcommit_memory=2 with sysctl to turn on explicit overcommit control, and then try changing the value of vm.overcommit_ratio to see if that changes where your system dies.
Also, is the system actually crashing, or does it just get swaplocked and hang indefinitely when swap usage reaches 25%? See if you can get sysrq-m and sysrq-t data out of the system. You'll want to set kernel.sysrq=1 first.
-- Chris
