Server migration

[Sami Ketola]

> On 31 Oct 2016, at 13.11, Tanstaafl <tanstaafl at libertytrek.org> wrote:
> 
> On 10/30/2016 5:32 AM, Sami Ketola <sami.ketola at dovecot.fi> wrote:
>> On 28 Oct 2016, at 16.54, Tanstaafl <tanstaafl at libertytrek.org> wrote:
>>> Oh... I thought the --useuid option eliminated this problem?
>>> 
>>> https://imapsync.lamiral.info/FAQ.d/FAQ.Duplicates.txt
> 
>> It does not. There is no option at IMAP level to set the UID.
>> 
>> In this case —useuid seems to keep track on source:uid -> dest:uid
>> pairs on multiple syncs and uses uid numbers to avoid syncing mails
>> as duplicates instead of using headers to do that.
> 
> Ok, interesting. So... how does dsync do it? Or would it only work
> between two dovecot servers?
> 
> I'm interested in migrating from other servers (Office 365 in one case).

Dsync does not use IMAP protocol to store the mails to storage but instead uses the 
dovecot storage API to do that. Internally we can set what ever properties we want to
including IMAP UIDs and POP3 UIDLs. 

Migrating from legacy system should then be done by pulling the mails from the
legacy platform by using the imapc connector and storing them by using the internal apis.

We can also store mails to imapc: location but in that case there is many properties that
will be lost due to limitations of the IMAP protocol.

Sami