Notes on scrub schedules for a two-disk mirror

2025-11-20

A monthly scrub is the usual advice and it is fine for a mirror of two 4 TB disks. The scrub takes about five hours here and I would rather it did not overlap with the nightly backup.

The systemd timer now runs on the second Sunday of the month at 03:00, and the backup job checks zpool status first and politely waits if a scrub is in progress.

So far: zero checksum errors in two years. Which is either reassuring or a sign that I should test the alerting path again.