Shared folder in a sharded cluster setup

[Aki Tuomi]

On 30.09.2016 17:10, Peer Heinlein wrote:
>
> Hi!
>
> 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
> filesystems.
>
> 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)!
>
> Peer
>
>
>

Just wanted to point out that asking about obox questions here is bit
futile since it's pro-only feature. Shared folders should not be a
problem if your backends can access same storage.

Aki