[Dovecot] repeating dsync - questions

[Bob Gustafson]

I'm moving/converting email from one system to another

The source system is:
Dual core x86_64
6GB memory
180 GB raid1 disks ext4
Fedora 9
Dovecot 1.0.15
Maildir format

The destination system is:
Dual core x86_64
2GB memory
1TB raid1 disks ext4
Fedora 18
Dovecot 2.1.15
sdbox format

I am moving mail in a series of steps:

0) cd ( to mail user home directory )
   mkdir Maildir

1) # rsync mail from source system (hoho4) to current (hoho0)
   time rsync -arv --times hoho4:/home/bobgus/Maildir/ /home/bobgus/Maildir/

This step takes about 37 minutes the first time

2) # dsync mirror/convert to sdbox format on current system
   time dsync mirror maildir:~/Maildir

This step takes about 858 minutes (!!)

Looking at -D messages indicates that dsync is deciding between
duplicates much of the time.

Looking at the results in a mail browser (Evolution), it seems fine,
although the latest mails are not there.

3) # pick up more current mail - use same script as in 1)
   time rsync -arv --times hoho4:/home/bobgus/Maildir/ /home/bobgus/Maildir/

This step takes about 5 minutes although this varies depending on the
amount of new mail.

4) # repeat the 2) dsync step
   time dsync mirror maildir:~/Maildir

This is where things look peculiar. When I look at the directory of
sdbox/mailboxes, I see duplicated directories

[bobgus at hoho0 sdbox]$ cd mailboxes
[bobgus at hoho0 mailboxes]$ ls
Apple Mail To Do
Apple Mail To Do_2a47983780615e5179600000ba55d82c
Deleted Messages
Deleted Messages_2847983780615e5179600000ba55d82c
Drafts
Drafts_2447983780615e5179600000ba55d82c
Important
Important_2947983780615e5179600000ba55d82c
INBOX
INBOX_1547983780615e5179600000ba55d82c
Sent
Sent_2547983780615e5179600000ba55d82c
Trash
Trash_2747983780615e5179600000ba55d82c

The 2nd dsync step has not completed yet. I'm wondering whether the
extra directory will be magically moved into the older directory.

(This is unlikely because the file names are duplicated in the new
directory)

-------

Is this expected behavior? Are there command changes I can make to speed
up the process? Eliminate the duplicate directories?