DB migrator NotEnoughDiskSpaceException does not mention which location

SYMPTOM:

DB migrator failed with below error, but the sonatype-work/nexus3/db had more than 10GB free space.

14:13:44 [main] INFO  c.s.n.d.m.l.ProvidingJobInfoListener - Detailed message: com.sonatype.nexus.db.migrator.exception.NotEnoughDiskSpaceException: Not enough disk space available. 10 Gigabytes of free disk space is required for the correct migration.

EXPECTED BEHAVIOUR:

The migrator checks the "db" and tmp location (java.io.tmpdir), so if the tmp doesn't have enough space, it would be nice if the error message mentions the location.

Also please update the document with this requirement.
https://help.sonatype.com/repomanager3/new-database-options/migrating-to-a-new-database

The migrator utility requires three times the disk space as your $data-dir/db directory.

Above should at least mention about the temp location.