[NGINX] cache process manager consume a lot of CPU at reload and has to be restarted

Maxim Dounin mdounin at mdounin.ru
Fri Apr 1 13:56:09 MSD 2011


On Fri, Apr 01, 2011 at 11:42:44AM +0200, Jérôme Loyet wrote:

> Hello,
> I had an issue last night with a 0.8.54 nginx instance. Around 1AM, a HUP
> signal is sent to log rotation. This nginx instance is set up as a reverse
> proxy to an apache/php and it does some cache. Here is the proxy_cache
> related conf I've set up.
> proxy_cache_path /CACHE levels=1:2:2 keys_zone=cache:256m inactive=1d
> max_size=20g;
> proxy_cache cache;
> Last night, the cache process manager has restarted well, but it has
> consumed all CPU available on the server. Moreover, the SAR command
> indicates that it did not seek, read or write on the disks (as the disk
> usage remains almost null). Our exploitation team had to restart nginx 40
> minutes later and it solves the problem.
> Has someone already experience such an issue ? Do you know why this could
> happened ?

Yesterday similar issue was discussed on russian mailing list, 


Cache manger was spinning in ngx_spinlock() waiting for cache lock 
to be released.  Cache lock was never released as it was hold by 
worker process which caught SIGSEGV while holding cache lock.

Maxim Dounin

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