Current box: CentOS 4.x (32 bit), dovecot 1.02, mbox format

New box (supposed): CentOS 6.x (32/64 bit ? ), dovecot 2.04, mbox format

The server have about 3.000 active users (unix users); /var/mail is about 100 GB; /home/Users about 150 GB

I read the docs and searched on the net, but still request hints for planning the migration.

32/64 bit? Tricks to avoid users get all messages ...?

Better first update the old server from 1.02 to 2.0x or ..?

Any hints/comment appreciated ;-)

Thanks, P.

1.02 dovecot.conf:

protocols = pop3 pop3s imap imaps listen = [::] log_path = /var/log/mail/dovecot.log info_log_path = /var/log/mail/dovecot.info.log log_timestamp = "%b %d %H:%M:%S " default_mail_env = mbox:~/:INBOX=/var/mail/%u mail_full_filesystem_access = yes first_valid_uid = 100 mbox_read_locks = dotlock fcntl mbox_write_locks = dotlock fcntl auth default { mechanisms = plain passdb pam { } userdb passwd { } user = root }