Recommended tool for migrating IMAP servers

[Webert de Souza Lima]

On Tue, Dec 5, 2017 at 8:54 AM, Sami Ketola <sami.ketola at dovecot.fi> wrote:

>
> Can't really do DNS change to test with one user as DNS change affects all
> users.


Yes, of course. For test purposes one could justchange the system's host
file and simulate a DNS change, after imapsync is complete
I meant a simple test just to see what happens at the client size, to see
what the user itself could notice.

On Tue, Dec 5, 2017 at 8:54 AM, Sami Ketola <sami.ketola at dovecot.fi> wrote:

>
> What we usually do is put layer of dovecot proxies in front of the legacy
> and destination platform and then have database
> with information if user has been migrated already and forward the
> connection to legacy or dovecot
> platform based on that info. That enables us to migrate user-by-user.


Cool, we do that too :D. We might have learned that from you even. In that
way users can use our Webmail from day 1 when migration starts.


On Tue, Dec 5, 2017 at 8:54 AM, Sami Ketola <sami.ketola at dovecot.fi> wrote:

>
> And both users and mail server admins do notice if there is IMAP UID or
> POP3 UIDL changes. Imagine
> what happens when millions of users suddenly start to redownload terabytes
> of data.
>
> Sami
>

That would just kill my cluster. Happened once due to NFS sharing hang.
Terrible day to be alive.


Regards,

Webert Lima
DevOps Engineer at MAV Tecnologia
*Belo Horizonte - Brasil*