Linux SoftRAID: Manage automatic check

[peter_b]

The Linux Kernel software RAID is configured by default to run an automated check of RAID arrays. That's good!
This check is happening in the background, but depending on your setup and use cases, you might want to re-schedule or disable it.

Here's how you can stop an ongoing check:

Code: Select all

$ echo "idle" > /sys/block/md0/md/sync_action

The automatic execution is configured using cron. For example, on a Raspbian it's at:

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/etc/cron.d/mdadm

To re-schedule when the check shall happen, edit that file. By default it looks like this:

#
# cron.d/mdadm -- schedules periodic redundancy checks of MD devices
#
# Copyright © martin f. krafft <madduck@madduck.net>
# distributed under the terms of the Artistic Licence 2.0
#

# By default, run at 00:57 on every Sunday, but do nothing unless the day of
# the month is less than or equal to 7. Thus, only run on the first Sunday of
# each month. crontab(5) sucks, unfortunately, in this regard; therefore this
# hack (see #380425).
57 0 * * 0 root if [ -x /usr/share/mdadm/checkarray ] && [ $(date +\%d) -le 7 ]; then /usr/share/mdadm/checkarray --cron --all --idle --quiet; fi