authcachesize base option specifies the maximum number of concurrent users/entries in the user/authentication cache.
The Messaging Server can cache the results of LDAP user lookups and successful authentication (e.g., when logging into IMAP, POP or SMTP). The
authcachesize option defines the number of authentication user cache entries. A higher setting for
authcachesize improves performance while using more memory. A lower setting reduces performance and reduces the amount of memory used.
The default value is: 10000