CentOS / RHEL:come rimuovere uno specchio con mdadm

Il post descrive la procedura per rimuovere il mirror con mdadm. L'esempio qui utilizzato ha RAID1 creato con i dispositivi /dev/sdb e /dev/sdc. Rimuoveremo il dispositivo /dev/sdb . Per cominciare, non creare prima il mirror RAID1.

Passaggi

1. Crea un dispositivo raid1 con i dischi /dev/sdb e /dv/sdc :

# mdadm -Cv /dev/md0 -l1 -n2 /dev/sdb /dev/sdc
mdadm: /dev/sdb appears to contain an ext2fs file system
    size=2097152K  mtime=Wed May  8 12:39:49 2013
mdadm: Note: this array has metadata at the start and
    may not be suitable as a boot device.  If you plan to
    store '/boot' on this device please ensure that
    your boot-loader understands md/v1.x metadata, or use
    --metadata=0.90
mdadm: /dev/sdc appears to contain an ext2fs file system
    size=2097152K  mtime=Wed May  8 12:39:53 2013
mdadm: size set to 2096116K
Continue creating array? y
mdadm: Defaulting to version 1.2 metadata
mdadm: array /dev/md0 started.

2. Controlla lo stato del dispositivo md :

# cat /proc/mdstat 
Personalities : [raid1] 
md0 : active raid1 sdc[1] sdb[0]
      2096116 blocks super 1.2 [2/2] [UU]

unused devices: <none>

3. Contrassegna il disco /dev/sdb come guasto nel mirror:

# mdadm /dev/md0 --fail /dev/sdb
mdadm: set /dev/sdb faulty in /dev/md0

4. Rimuovere il disco /dev/sdb dal mirror:

# mdadm /dev/md0 --remove /dev/sdb
mdadm: hot removed /dev/sdb from /dev/md0

5. Ricontrolla lo stato del dispositivo md :

# cat /proc/mdstat 
Personalities : [raid1] 
md0 : active raid1 sdc[1]
      2096116 blocks super 1.2 [2/1] [_U]

unused devices: <none>