Dual Dovecot setup

[dovecot.dirk at o.banes.ch]

Hi all,

I´m using dovecot successfully since some years.
My current setup is postfix and dovecot on one vserver.

This works great so far.

            +--------------------+
eMail in    | VSERVER1           |
+---------->+ MX 1 (Master)      |
            | POSTFIX MTA        |
            | DOVECOT ALL Folders|
            +-----^--------------+          
                  |
                  |eMail Backup
                  |
                  |
           +------+---------+
           | VSERVER2       |
 eMail in  | MX 2 (Backup)  |
 Backup    | POSTFIX MTA    |
 +--------->                |
           +----------------+

However now I want to change this setup to have on box in my home which
holds all eMails and Folders which are not in the Inbox.
This is due to disk space and privacy concerns.

Even if the home connection is very very stable for the case something
fails while on vacation the content of the inbox of every user
should always stay on the VSERVER1 as well - until it is moved to one
subfolder.

            +---------------+              +-------------+
eMail in    | VSERVER1      |              | HOMEBOX     |
+---------->+ MX 1 (Master) |    ?SYNC?    | DOVECOT     |
            | POSTFIX MTA   +--------------> ALL FOLDERS |
            | DOVECOT INBOX |              |             |
            +-----^---------+              +-------------+
                  |
                  |eMail Backup
                  |
                  |
           +------+---------+
           | VSERVER2       |
 eMail in  | MX 2 (Backup)  |
 Backup    | POSTFIX MTA    |
 +--------->                |
           +----------------+

I read into documentation and also did a fair share of googeling but I
could only identify possible solutions which I´m not sure they will work.
a) dsync - Can dsync only sync the Inbox ?
b) fetchmail - Unsure how an eMail moved from Inbox (Homebox) to another
folder would get removed from the inbox of the vserver1

Therefore I hope maybe someone of you has an idea how this can be archived.

Thank you

best regards

Dirk