Proxy Cache: how much shared memory is "enough"?

Server NGINX
1

Hi,

I’m planning to deploy some big websites which will make heavy usage of
proxy cacheing (e.g. 1.5 million actively accessed objects in cache).
The
ratio of plain HTML vs images should be about 50/50 if that does have
any
impact on the scenario itself. Now the question which came up is how
much
Shared Memory for such a cache is enough. The docs don’t really say very
much about that. So may be one of you can give me a hint on how much
memory
is suitable for such a deployment.

Thanks in advance.

Regards,
Christian

2

Hello!

On Mon, Dec 10, 2012 at 10:37:30PM +0100, Christian Bönning wrote:

I’m planning to deploy some big websites which will make heavy usage of
proxy cacheing (e.g. 1.5 million actively accessed objects in cache). The
ratio of plain HTML vs images should be about 50/50 if that does have any
impact on the scenario itself. Now the question which came up is how much
Shared Memory for such a cache is enough. The docs don’t really say very
much about that. So may be one of you can give me a hint on how much memory
is suitable for such a deployment.

Each object in cache uses 128 bytes of memory in keys shared
memory zone on 64-bit platforms, as outlined on wiki here:

http://wiki.nginx.org/HttpProxyModule#proxy_cache_path

So for 1.5 mln objects you’ll need about 200M of memory.

–
Maxim D.

3

Seems that I should have read the docs better :wink:

Thank you, Maxim.

Regards,
Christian

2012/12/11 Maxim D. [email protected]