Moving out of Google Suite (Workplace). Part 2: mailboxes and users migration.

Since the secondary domain mentioned in Moving out of Google Suite (Workplace). Step 1: mail server. did not have many users, I went with manual migration to investigate which steps would be required and to document them.

The steps are:

  1. Create users in MIAB (manually or via Mail-In-A-Box API).
    1. Don't forget to securely save the passwords! First, you will need to provide your users with them, second, unfortunately MIAB does not have password change as a self-service option by default - and you will have to change passwords manually for you users unless you enable a Roundcube plugin.
  2. Email your existing users in GSuite with an instruction, which mentions:
    1. Mail:
      1. Mail-In-A-Box URL for webmail: https://<>/mail
      2. Username and password
      3. For mobile and desktop clients: set up the account as Exchange/ActiveSync (preferred way as it will setup Mail/Contacts/Calendar in one step).
      4. Instruction how to migrate their mail from GSuite to MIAB (more on this below).
    2. Google Drive / Photos:
      1. Download NextCloud apps on mobile and laptops / desktops.
      2. Set up sync for laptops / desktops.
      3. Set up InstantUpload for mobile.

I would like to share more on IMAP mail migration.

There are very few tools to migrate your IMAP mail box to another server and most of them require some DevOps expertise.

The only tool I found to be friendly to non-tech-savvy users is Mailbox Imapsync Online by Gilles LAMIRAL.

The tool allows to sync mailboxes under 3GB to another server for free.

To migrate mailboxes over 3GB one needs to purchase a license (from €30 to €120 at the time of me writing this article) which provides unlimited number of syncs of any size.

Purchase of the license happens directly from the author and I find this fact utterly attractive, this is another example of self-hosting and rational decentralisation.

My main mailbox is over 10GB so free Imapsync was not a solution and paid one was not possible due to SWIFT issues.

I used the following workaround:

  1. Set up both source and target mail accounts in your mail client (OSX in my case)
  2. Copy all mail from source to target account in mail client
  3. This process is not too stable in so I ended up with ~30k of duplicate emails in the target account
  4. After some experiments I found out that IMAPdedup does deduplication perfectly.