On 2022-10-10 14:57, Ian Evans wrote:

> If we want to make a one-off backup prior to the migration, is
> shutting down postfix and running
> tar czf mailstorage.tgz /path/to/mail okay?
>
> Thanks.

I would say it should be ok as long as its going to be the same setup,
but if you are expecting to upgrade dovecot or any other related
package, I would then recommend to perform upgrades before migrating and
taking the backup, so to guarantee everything is going to be working.