Re: dst cache overflow

On Tue, 14 Aug 2007 18:06:46 +0200
Tobias Diedrich <ranma+kernel@xxxxxxxxxxxx> wrote:

Hello,

I suspect I'm seeing a slow dst cache leakage on one of my servers.
The server in question (oni) regularly needs to be rebooted, because
it loses network connectivity. However, netconsole and syslog shows that the
machine is still running and the kernel complains about "dst cache
overflow".

I have since installed a monitoring script, which stores the output of
both "ip route ls cache | fgrep cache | wc -l" and the 'entries' value
of /proc/net/stat/rt_cache (as suggested in
http://www.mail-archive.com/netdev@xxxxxxxxxxxxxxx/msg02107.html)
and produces a nice rrd graph:

http://uguu.de/~ranma/route-month-oni.png
So entries is growing more or less constantly, while the number of
active routes (not visible on the graph due to being too small) is
relatively constant.

Comparing this to another host running the exact same kernel:
http://uguu.de/~ranma/route-month-ari.png
Here cached_routes and entries barely differ at all.

The funny thing is, both hosts are running the exact same kernel
and use more or less the same iptables rules.

So I'm not sure what would cause the dst cache to leak only on host
oni?


Could you send the result of these commands on oni and ari ?

ip route ls
grep . /proc/sys/net/ipv4/route/*

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