proxy_cache calculating size error under SSD drive but not SATA drive

[Maxim Dounin]

Hello!

On Thu, Jul 18, 2013 at 07:46:01AM -0400, feanorknd wrote:

> Hello:
> 
> I think I am on the right way, but not sure...
> 
> The scenario:
> 
> - Have 2 drives:
>                            -> SSD drive - XFS - default options (with
> noatime, discard) - almost empty
>                            -> SATA drive - XFS - default options - almost
> empty
> 
> - Kernel variables, shared memory, ulimits, max-file, etc... all correctly
> configured
> 
> - Nginx and virtualhost correctly configured.
> 
> - proxy_cache_path <PATH> levels=1:2 keys_zone=catalogo_fotos:2500m
> max_size=2500m inactive=120d;
> 
> 
> Ok.. here I am... it depends of the path... the problem is:
> 
> - If the path is at SATA drive -> cache is growing until maximum 2500m are
> reached... no problem here. Normal..
> - If the path is at SSD drive -> cache is not growing until limit... it
> stale... problem... why?

Try looking into this ticket:

http://trac.nginx.org/nginx/ticket/157

With XFS, a file size reported on just created files before a file 
is closed is incorrect, and this might confuse nginx.

[...]

> What is that "http file cache size: 640039" ???? That number, which way is
> calculated??? What it is?

This is the cache size in blocks.

-- 
Maxim Dounin
http://nginx.org/en/donation.html