Applying Dovecot for a large / deep folder-hierarchy archive.

[Aki Tuomi]

On 26.6.2019 22.12, Arnold Opio Oree via dovecot wrote:
> Hello to you all,
>
> I'd like to ask about my intended application of Dovecot to create a folder-hierarchy for storing our enterprise emails, which are treated as live data rather than archives for compliance or occasional / reactive retrieval.
>
> The data is presently not that large (a few gigabytes), but it is expected to grow rapidly. Up to this stage the data has been contained
> in a Microsoft Exchange mailbox (2013), and then in an offline PST. The move to the offline PST was by necessity, as the large number of
> folders, and depth of hierarchy to my best understanding caused the exchange server / outlook / evolution mail clients to begin to
> malfunction. To cope with this the archive was broken up and the bulk stored in the offline PST and the most active components stored in
> online Exchange mailboxes.
>
> I have some understanding of the fs mbox format, and also the mitigations to be made for certain characters / strings. My main concern is whether Dovecot is likely to be able to cope well with a large number of folders / depth of hierarcy.
>
> I will really appreciate any help / advice you can give.
>
> Best regards,
>
> Arnold Opio Oree
>

Hi!

Dovecot 2.2.34/2.3 supports unlimited folder depth, the only limiting
factor is that the total name may not exceed 4096 bytes. Also individual
folder names may not exceed 255 bytes.

Prior to that the limit is 255 per folder up to 16 levels.

I can't recommend using 'mbox' storage format, please consider using
maildir or sdbox instead.

Aki