Piecemeal migration

[Shelley Waltz]

I wish to migrate imap accounts from my current cyrus-imapd-2.2.3-4 on RHEl3
to cyrus-imapd-2.3.7 on RHEL5.  I have the new server installed and the db
formats will ramin the same on both servers except for deliver.db and
tls_sessions.db which will change from berkeley to skiplist.  My
understanding is that I can simply start with fresh db on the new server
and do not need to migrate these(copy and convert).

I will be migrating about 250 accounts of 1GB or less.  I need to do these in
5-10 at a time to minimize complications and downtime.  Last time I did
this, it worked out well, migrating from 1.6 to 2.2 even though I did need
to convert dbs.  I will set up alias forwarding for the migrated accounts
and once all migrated, change TTL on DNS and modify records to move
completely to new server.

I know I need to copy from olde server to new server,
(1) /var/lib/imap/user/"a-z"/"username".sub,seen
(2) /var/lib/quota/"a-z"/user."username"
(3) /var/lib/imap/sieve/"a-z"/"username"/
and
(4)/var/spool/imap/"a-z"/user/"username"/

Additionally, and this was the sticky part the last time, is the
mailboxes.db which contains the INBOX/folder structure.  Last time, I
migrated my LDAP database(for authentication) and the entire
mailboxes.db(dumped to flatfile and then recreated on the new server)
before beginning to migrate the accounts in batches.  The issue arose,
however, of this being out of sync with some mailboxes in time as users
changed their folders.  Soooo, my question is, is there a way to update or
add new mailboxes individually using the flatfile information I can
extract from the old server?  Can one easily do this without stopping the
server?

Any suggestions are greatly appreciated!
S.Waltz