"No space left on device" for temp cache - v1.7.4

[arraisgabriel]

Hi, recently we noticed that the version 1.7.3 added a feature important to
our infrastructure: "cache revalidation now uses If-None-Match header if
possible.".
So we changed part of our cache to the 1.7.4 version, but something strange
started to happen, at certain point of disk usage nginx started to return
500 to all requests with this kind of message in the error log:

[crit] 12908#0: *7209656 open() "/cache/nginx_tmp/0002938835" failed (28: No
space left on device) while reading upstream, client: xxx.xxx.xxx.xxx,
server: , request: "GET http://xxxxxxxx.net/ HTTP/1.1", upstream:
"http://xxx.xx.xxx.xxx:80/", host: "xxxxxxxx.net"

It looked like that there wasn't enough space in the temporary cache
directory. But running df -h (and after sync && df -h) the result was:

[user at nginx ~]$ df -h
Filesystem      Size  Used Avail Use% Mounted on
/dev/xvda1      7.8G  2.3G  5.4G  30% /
devtmpfs        3.7G   20K  3.7G   1% /dev
tmpfs              3.7G     0     3.7G   0% /dev/shm
/dev/xvdb        40G   12G   27G  31%  24% /cache      
---------------------------------------- used for cache

I think that is important to know that a very similar configuration is
running well in a 1.7.2 server with the same specs and without the cache
revalidation directives.

This is my cache path configuration:

proxy_cache_path  /cache/nginx levels=1:2 keys_zone=cache:1500m max_size=27G
inactive=1200m;


Can you help?

Gabriel Arrais.

Posted at Nginx Forum: http://forum.nginx.org/read.php?2,253185,253185#msg-253185