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

[Maxim Dounin]

Hello!

On Thu, Sep 11, 2014 at 10:15:43AM -0400, arraisgabriel wrote:

> 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

ENOSPC from open() likely means you've run out of inodes, not disk 
space.  Try looking into "df -i", it may be helpful.

-- 
Maxim Dounin
http://nginx.org/