SQL Server on Linux, an unmount error is output to the screen upon reboot
The systemd unit file for the SQL server should be locally extended by a dependency on the /datadir this will make sure the start is done after the mount and the unmount waits for the stop. The most generic option to do this would be

RequiresMountsFor=/datadir


I think it automatically depend on the installation path of the scripts already.

Note that you do not need to modify the systemd unit files in the library directory but you can amend them in the /etc/systemd/system/&lt;sqlserver&gt;.service