On Wed, 18 Sep 2013 18:28:18 -0700, Andy Isaacson adi@hexapodia.org wrote:
On Wed, Sep 18, 2013 at 05:43:13PM -0700, Gordon Morehouse wrote:
Thanks, Roger. I'm still not sure what finally caused the OOM-killer crash this morning after almost a couple weeks (?) of uptime. I was also seeing additional clock jump messages but didn't have time to diagnose it. The Pi does not have a battery-backed RTC so it requires a clock set at each start, accomplished by 'ntpdate' and kept in time with, in my case, 'openntpd'. But, 'openntpd' wasn't complaining at the time of the clock jumps that were reported by Tor, and AFAIK 'ntpdate' is not scheduled to run periodically, so I don't know what's causing it yet.
The "Your system clock just jumped 100 seconds forward" messages are unlikely to be due to NTP. Much more likely the Tor daemon was blocked for a significant time period, due to swapping or similar.
I figured it might have been a really bad clock, but that seemed unlikely. I wouldn't remotely be surprised if what you are saying is true as the Pi is pretty memory-constrained. I'll try to correlate/reproduce it.
When the Pi goes to swap, it's getting desperate - it's swapping to a Class 10 microSD card. :/
What does top show? In particular the "Mem" and "Swap" lines, and the process line for the Tor process. Here's a large Xeon server running 4 Tor daemons:
top - 18:26:40 up 16 days, 18:18, 1 user, load average: 3.79, 3.95, 3.96 Tasks: 99 total, 4 running, 95 sleeping, 0 stopped, 0 zombie Cpu(s): 69.0%us, 5.1%sy, 0.0%ni, 19.4%id, 0.0%wa, 0.0%hi, 6.5%si, 0.0%st Mem: 8176824k total, 6361748k used, 1815076k free, 36336k buffers Swap: 0k total, 0k used, 0k free, 183736k cached
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 14567 debian-t 20 0 2003m 1.8g 21m R 109 22.7 4477:00 tor 30171 debian-t 20 0 2390m 1.8g 20m R 100 23.6 13544:10 tor 18891 debian-t 20 0 1800m 1.5g 23m R 86 19.8 3134:31 tor 8798 debian-t 20 0 324m 149m 31m S 21 1.9 36:48.05 tor
A similar picture from your RPi might shed some light on the situation.
*Typically,* tor consumes about 25-40% of all available RAM to handle 300-800 circuits and 0.5-2Mbps of traffic (it boots with 485MB physical available after all is said and done). It always seems to get OOM-killed when I'm sleeping.
Best, -Gordon M.