Hi Michael,

2018-01-07  9:38:18 139980432365760 [Note] InnoDB: Highest supported file format is Barracuda.
2018-01-07 10:11:48 139980432365760 [Note] InnoDB: 128 out of 128 rollback segments are active.

This is really unacceptable behaviour. It looks like you have encountered
https://jira.mariadb.org/browse/MDEV-9843 where this exactly same behaviour has been documented.

Can you reproduce the delay on every startup? Stack traces (from http://poormansprofiler.org/ or "perf top -g" or similar) during this startup delay would be very useful.

With best regards,