Migrating to new server, questions about recommended configuration.

Hello! I'm moving Dovecot from a FreeBSD Jail (on ZFS using Maildir) to an Amazon EC2 Debian host.

1. I was on Dovecot 2.1 on my FreeBSD system but upgraded it to 2.2 so I could use dsync for the transfers. Is dsync the best way to migrate my data?

2. On the new Debian host, is there a better filesystem than EXT4 that I should use for the mail storage?

3. On the new host, is mdbox generally recommended over maildir? Especially when mixed with dsync?

4. Does dsync work as a good backup tool to keep a mirror of my live system?

5. I don't know Linux as well as FreeBSD but is it recommend to setup LVM and take daily snapshots as part of the backup plan? Do LVM snapshots cause any problems with Dovecot in the case of a rollback/restore?