# NGINX cache. Real meaning of zone\_size

**URL:** <https://www.ruby-forum.com/t/nginx-cache-real-meaning-of-zone-size/213530>\
**Category:** NGINX\
**Created:** [November 4, 2011, 3:04pm UTC](https://www.ruby-forum.com/t/nginx-cache-real-meaning-of-zone-size/213530 "2011-11-04T15:04:56Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![luislavena](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/l/0ea827/32.png) [@luislavena](https://www.ruby-forum.com/u/luislavena)\
**Post date:** [November 4, 2011, 3:04pm UTC](https://www.ruby-forum.com/t/nginx-cache-real-meaning-of-zone-size/213530/1 "2011-11-04T15:04:56Z")

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Hello, I read from the list

“zone\_size” is a size of keys\_zone, i.e. shared memory zone used to  
store cache keys (some minimal metadata about cached pages, about 64  
bytes on 32-bit platforms).

but what does this practically mean ?

Let say a new request arrive and the request has to be cached. What does  
NGINX do if the “space” in the shared memory is over ? It delete the  
oldest file in the cache (and the key too) ?

Is there a rule to size this parameter ?

Thanks

–  
Simone