According to the nginx documentation, the proxy_cache_path directive has a parameter called keys_zone
. The documentation also refers a concept of "shared memory zone".
In addition, all active keys and information about data are stored in a shared memory zone, whose name and size are configured by the keys_zone parameter. One megabyte zone can store about 8 thousand keys.
Is the "shared memory zone" a general term? or a specific term used by nginx? What does the "shared" exactly mean?