Maintenance in short

(complete status)
storagegrid-status

(stop a service)
service ldr stop

(start a service)
service ldr start
service ldr status

(unmount and reformat volume on a storage node)
umount /var/local/rangedb/1
cp /etc/fstab /etc/fstab.orig
grep -v rangedb/1 /etc/fstab.orig > /etc/fstab
reformat_storage_block_devices.rb

(repair the volume from the admin node!)
repair-data start-replicated-volume-repair --nodes DC2-S2 --volumes 0001
repair-data start-ec-volume-repair --nodes DC2-S2 --volumes 0001