[MlMt] Moving ISP/IMAP host

[Bill Cole]

On 2022-09-02 at 21:23:37 UTC-0400 (Sat, 03 Sep 2022 11:23:37 +1000)
Gavan Schneider via mailmate <mailmate at lists.freron.com>
is rumored to have said:
[...]
> Plan:
> Put all my “eggs” in what appears to be the much better basket
>
> Proposed process, and your thoughts and wisdom welcome here —
> 1. Take IMAP accounts “off-line”in MlMt
> 2. Switch DNS of the relevant domain name to the good provider
> 4. Create the email accounts on this provider
> 5. Change the IMAP account settings in MlMt
> 6. Wait for the DNS change to propagate
> 7. Bring accounts “on-line” in MlMt… and
> 8. Allow the synchronisation process to happen, with lots of messages 
> getting loaded on the ISP server (I hope)

That will not be what happens. Instead, MM will toss all the local 
messages. You will have pristine email accounts, unsullied by email.

> 9. Clean-up in account maintenance mode on bad provider once I get 
> access again (find any missing messages, etc.)
>
> I have the bandwidth to cover this and speed is good so it should all 
> happen in reasonable time provided I am correct in my process.
>
> So, have I made any silly assumptions or omissions in the above?

Not silly, as it is understandable and not entirely unreasonable: that 
MM's local copy of your mail is anything more than a 100% cache of the 
server view of the message store. Whenever the server disagrees with MM 
about what messages exist and what their states are, the server wins 
unconditionally.

The tool you want is imapsync: https://imapsync.lamiral.info

There's a MacPorts port that's relatively recent, and I suspect that 
Homebrew has a recipe for it. If you have command line access and can 
install your own tools, it runs on anything Unix-like and you may find 
it faster to run server-to-server rather than via your Mac.

Another MacOS tool that I like a lot for client-side message store 
wrangling is (not free) Emailchemy: https://weirdkid.com/emailchemy/.

Alternatively, you COULD use MM to export your entire message store in a 
form that it can re-import. Then you would switch the settings, let MM 
wipe out its cache, and import the messages.


-- 
Bill Cole
bill at scconsult.com or billcole at apache.org
(AKA @grumpybozo and many *@billmail.scconsult.com addresses)
Not Currently Available For Hire