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. This pair of
settings for :cyrusman:`imapd.conf(5)` control hashing behavior:
Regardless of those settings, the per-user state information will always be hashed.