Re: Machine dies under heavy I/O or network-access ..?

[Andrew Morton]

"Christiaan den Besten" <chris@xxxxxxxxxxx> wrote:
>
> We have recently installed two new Usenet feeders, but are having issue's keeping them alive under 'heavy' load. Both are SuperMicro 
>  based models with onboard Intel GB NICS and have a Areca 16 ports SATA-II controller. Both are Dual Xeon 2.8 with 4G ram, swap 
>  disabled. Filesystems are tmpfs, ext3 and xfs.
> 
>  Using plain vanilla 2.6.12+ these machines will usually crash within an hour or so. With -mm patched kernels this timeframe 
>  increases somewhat (seen 5 days). ( Crash means: none of the processes are responding, but machines does reply ping requests ... ). 
>  I have not yet been able to connect a serial for logging, and the screen does not come out of screen blanking on keyboard access...
> 
>  These machines handle aprox 200mbit on eth0 and 400mbit on eth1, the Areca driver will write +/- 20Mb/s to the disks and sometimes 
>  have to read upto 60Mb/s as well (just to give an impression of what the load is .. )
> 
>  Today I noticed the following assertion in dmesg:
> 
>  ---
>  e1000: eth0: e1000_watchdog_task: NIC Link is Up 1000 Mbps Full Duplex
>  KERNEL: assertion (!sk->sk_forward_alloc) failed at net/core/stream.c (279)
>  KERNEL: assertion (!sk->sk_forward_alloc) failed at net/ipv4/af_inet.c (148)
>  ---

Add some swapspace.



Before it hangs, do

	echo 1 > /proc/sys/kernel/sysrq

and test that alt-sysrq-T produces output.

When it hangs, do alt-sysrq-p a few times and record the result.  Then do
alt-sysrq-t a few times and record the result.

You'll probably need a serial console to record the results.
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