btrfs-scrub.service

[Unit]
Description=Check volume for errors
Documentation=man:btrfs-scrub
After=fstrim.service

[Service]
Type=oneshot
ExecStart=/usr/bin/sh -c 'for i in $(grep btrfs /proc/mounts | cut -f1 -d" " | uniq); do echo scrubbing $i; btrfs scrub start -Bd $i; done'
IOSchedulingClass=idle
CPUSchedulingPolicy=idle