mdadm

CautionSoftware RAID (md)

mdadm --detail /dev/md0

Manages md RAID. [U_] in /proc/mdstat reveals a missing member; swap disks with --fail/--remove/--add.

Examples

cat /proc/mdstatRAID health at a glance

Syntax

mdadm --detail <md> / cat /proc/mdstat

Before you run it

Triple-check device names during swaps.

Related commands

smartctlDisk health via SMART
lsblkList block devices
dmesgShow kernel ring buffer

The same reference, with no signal at all

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