> On Jan 5, 2018, at 6:38 PM, Boris S. <postfix-us...@dva.myftp.info> wrote:
>
> But I wonder what would be best practice to do a migration of an existing
> configuration.
>
> Is it possible to have my original, working setup as a starting point in a
> new instance?
Yes. The key constraint is that no two instances may share:
* $config_directory
* $queue_directory
* $data_directory
* master.cf "inet" entries that resolve to a common [IP:]port
Otherwise, you may clone most of an existing main.cf and master.cf
into a new instance, making sure to not clobber the "multi_instance_..."
parameters, the instance-specific directories, or create overlapping
TCP listeners.
Doing this on a live system can be a bit tricky if there are already
queued messages, and the role of the default instance changes in a
way that is not appropriate for delivering deferred mail. Draining the
queue during a maintenance window is before switching to multi-instance
is probably simplest.
--
Viktor.
