Nginx variables_hash error

[Maxim Dounin]

Hello!

On Tue, Apr 19, 2011 at 05:40:26AM -0400, Nam wrote:

> Hi Guys, I have started getting this error on some of my servers today.
> I have an automated system which generates configuration files based
> upon how many customers we have. Our nginx servers currently run MANY
> sites (server directives) and all of a sudden we started getting the
> follow error when trying to do an nginx reload...
> 
> [emerg]: could not build the variables_hash, you should increase either
> variables_hash_max_size: 512 or variables_hash_bucket_size: 64
> configuration file /etc/nginx/conf/nginx.conf test failed
> 
> Any ideas on what is causing this and how I could resolve it.

http://wiki.nginx.org/Optimizations#Hash_Tables

Setting bigger variables_hash_max_size and/or 
variables_hash_bucket_size will indeed help.

> I have
> looked for a directive variables_hash_max_size or
> variables_hash_bucket_size on the wiki and I cannot find any
> documentation covering a directive with those names. Is this a
> compilation option I need to change to allow for more configurations?

No.  This is just configuration directives of http core module, 
allowed at http{} level.  Undocumented due to ENOTIME, but they 
are mostly covered by generic hash documentation.

> The odd thing is, we have multiple servers and only some of the servers
> are having this issue. We are using nginx 0.8.53 on these servers.

This only occurs when using many (or long) variables in 
config.

Maxim Dounin