"Too many open files"

[Pascal Maes]

Hello

We have :

Solaris 10, cyrus-imapd 2.2.12, Berkeley DB 4.3.28
and about 25000 mailboxes (INBOX).

We have already put the limit of rlim_fd_max and rlim_fd_cur to 65535,
but there are still errors like :

DBERROR: opening /export/var/imap/user/U/uzabumuhire.seen: Too many open files
IOERROR: opening quota file /export/var/imap/quota/U/user.uzabumuhire: Too
many open files
IOERROR: opening /export/var/spool/imap/U/user/uzabumuhire/cyrus.header:
Too many open files
DBERROR: opening /export/var/imap/user/U/spigeon.seen: Too many open files


In the imapd.conf we have :

annotation_db: berkeley
duplicate_db: berkeley-nosync
mboxlist_db: berkeley
seenstate_db: berkeley


What should we make to change these to "skiplist" ?

Thanks
-- 
-- Pascal --