Directory Hashing

Cyrus IMAP uses directory hashing for per-user state information, including quotas (with quota_db: quotalegacy), sieve, subscriptions and seen information. Sites with lots of users may wish to hash their mail spool, too. Cyrus provides mechanisms for this.

Hashing behaviour is controlled by the hashimapspool and fulldirhash settings.

Regardless of those settings, the per-user state information will always be hashed.