Nginx cache - could not allocate node in cache keys zone

Server NGINX
1

I have four servers in a pool running nginx with proxy_cache. One of the
nodes started spewing “could not allocate node in cache keys zone”
errors
for every request (which gave 500 status). I did a restart and it
started
working again.

What conditions cause that error in general?

If it happens again is there anything I can do to try and determine the
root cause?

2

Same condition on two more of the servers in the same pool. Reload
doesn’t
resolve the issue, but restart does. No limit being hit on disk space,
inodes, open files, or memory.

3

This is nginx/1.9.0 BTW

4

At a guess I would say your key zone is full. Try increasing the size of
it.

5

One other question - is the key zone shared between the worker
processes?
Or will each worker allocate its own copy?

6

I will try that now - but shouldn’t it be evicting a key if it can’t fit
a
new one?

On Thu, Mar 10, 2016 at 2:38 PM, Richard S.
[email protected]