Stefan Neufeind wrote:
Here we're using one machine for fetching (exclusive at the moment) with
about 50 fetchers and a local Bind-resolver in caching-nameserver setup.
Bandwidth of the fetchers is 5 to 10mbit inbound roughly.
What I see is that during fetching java is taking 99.9% cpu (all
userland). At the point where the server "stalls" this changes to 99.9%
on system-usage (writing something to disc?). It stalls for about 30
seconds or a bit more.
This sounds suspiciously like a pagedaemon - what's the swap usage?
Hmm - I don't know where to look for the cause of these stalls, since
you don't see what it really does at that point (in logs or so).
PS: Your thoughts on this are very much appreciated.
Get a thread dump (kill -SIGQUIT) from that java process. When you look
at top(1), which of the pid states is the most common? R (runnable) or D
(disk-wait)? And check the swap usage, as mentioned above.
Other ideas: run your fetcher in non-parsing mode. It could be that the
parsing step is taking so much CPU. Also, mount your volumes
async,noatime - you can afford to lose some working data if the machine
crashes.
--
Best regards,
Andrzej Bialecki <><
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