# Possible cached file corruption with aio\_write enabled

**URL:** <https://www.ruby-forum.com/t/possible-cached-file-corruption-with-aio-write-enabled/244678>\
**Category:** NGINX\
**Created:** [May 25, 2016, 2:16pm UTC](https://www.ruby-forum.com/t/possible-cached-file-corruption-with-aio-write-enabled/244678 "2016-05-25T14:16:30Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![Sadaf\_N](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/858c86/32.png) [@Sadaf\_N](https://www.ruby-forum.com/u/Sadaf_N)\
**Post date:** [May 25, 2016, 2:16pm UTC](https://www.ruby-forum.com/t/possible-cached-file-corruption-with-aio-write-enabled/244678/1 "2016-05-25T14:16:30Z")

</div>

Hello,

I’ve recently upgraded one of the nginx servers within a caching  
(proxy\_cache module) cluster from 1.8.1 to 1.10 and soon after I noticed  
unusually high number of various errors only on that server which I  
eventually pin pointed to a mismatch between the actual cached file size  
on  
disk and size reported in file metadata (either content-length or  
something  
else). Apparently, cached files on 1.10 are cut short and miss up to few  
hundred kilobytes at their ends (for files over 100 MB in total size).  
For a  
few files I checked, the larger file was, more content it missed at the  
end.  
Eventually I found the culprit to be aio\_write which I enabled the same  
time  
I upgraded nginx. Disabling it and removing all already cached files  
resolved the problem.

Relevant directives:

```
thread_pool default threads=4 max_queue=65536;
sendfile on;
aio threads=default;
aio_write on;
# output_buffers are used if sendfile is not used
# output_buffers 8 512k;
read_ahead 1;

proxy_cache_path /cache ... use_temp_path=on;
proxy_buffering on;
proxy_buffers 32 64k;
proxy_busy_buffers_size 128k;
proxy_temp_file_write_size 128k;

```

OS is Linux 4.1.

Thanks,  
Vedran

Posted at Nginx Forum:

> **[Possible cached file corruption with aio\_write enabled](https://forum.nginx.org/read.php?2,267142,267142#msg-267142)**
>
> Hello, I've recently upgraded one of the nginx servers within a caching (proxy\_cache module) cluster from 1.8.1 to 1.10 and soon after I noticed unusually high number of various errors only on that server which I eventually pin pointed to a mismatch...