Shared folder in a sharded cluster setup

Peer Heinlein p.heinlein at
Fri Sep 30 14:10:16 UTC 2016


With Dovecot Director and Proxy or the new (great!) TAG-feature from
Dovecot it's easy to set up a shared IMAP-Cluster with individual local

But I'm unsure if it's possible to build a setup where shared mailboxes
still can work.

If user A is on Cluster (1) and user B is on (2),
and Cluster (1) does not have access to the mail-home from B on (2),

then user A can not reach the shared folders provided from User B on (2).

I hope that there is a kind of backend-proxy-mechanism, so that the imap
process of A on (1) can imap-proxy the requests for the shared folder to
a node from cluster shard (2).

And: To be exact, the imap process on (1) should forward the request to
cluster (2) by the director system to make sure, that the connection
will terminate on the right active backend of User B.

This sounds like a special problem if local filesystems with mdbox are
used and I now the great features of using Dovecot on Object Store,
where every node can check out all mail-locations from all users.

But especially on obox-systems it is very important that requests for a
user are always terminated on the same backend. So how can shared
folders work there?! Node (1) can not checkout the shared folders from
User B if his obox storage is already active on another host (2)!


Heinlein Support GmbH
Schwedter Str. 8/9b, 10119 Berlin

Tel: 030 / 405051-42
Fax: 030 / 405051-19

Zwangsangaben lt. §35a GmbHG: HRB 93818 B / Amtsgericht
Geschäftsführer: Peer Heinlein -- Sitz: Berlin

More information about the dovecot mailing list