====== RAID ======
>debian:~# **cat /proc/mdstat**
<code>
Personalities : [raid1] 
md2 : active raid1 sdb2[0] sda2[1]
      975763866 blocks super 1.2 [2/2] [UU]
      bitmap: 5/466 pages [20KB], 1024KB chunk

md0 : active raid1 sdb1[0] sda1[1]
      995904 blocks [2/2] [UU]
      
unused devices: <none>
</code>

Problém s jedním zařízením (hdd1):
<code>
debian:~# cat /proc/mdstat
Personalities : [raid1] 
md0 : active raid1 hda1[0] hdd1[3](F) hdb1[1]
      1172608 blocks [3/2] [UU_]
      
unused devices: <none>
</code>

Rekonstrukce pole po výměně disku:
<code>
debian:~# cat /proc/mdstat
Personalities : [raid1] 
md0 : active raid1 hdd1[3] hda1[0] hdb1[1]
      1172608 blocks [3/2] [UU_]
      [=====>...............]  recovery = 28.0% (328768/1172608) finish=0.7min speed=18264K/sec
      
unused devices: <none>
</code>

===== Výměna disku =====
Výměna disku **sdb**

**Výchozí stav:**
<code>
root@pbx:~# cat /proc/mdstat
Personalities : [raid1] 
md2 : active (auto-read-only) raid1 sda6[0] sdb6[2]
      1174516 blocks super 1.2 [2/2] [UU]
      
md1 : active raid1 sda5[0] sdb5[2]
      877927288 blocks super 1.2 [2/2] [UU]
      
md0 : active raid1 sda1[0] sdb1[2]
      97653688 blocks super 1.2 [2/2] [UU]
</code>

**Oznaceni vadneho disku (partition):**
<code>
root@pbx:~# mdadm --manage /dev/md0 --fail /dev/sdb1
mdadm: set /dev/sdb1 faulty in /dev/md0
root@pbx:~#
root@pbx:~# mdadm --manage /dev/md1 --fail /dev/sdb5
mdadm: set /dev/sdb5 faulty in /dev/md1
root@pbx:~#
root@pbx:~# mdadm --manage /dev/md2 --fail /dev/sdb6
mdadm: set /dev/sdb6 faulty in /dev/md2


root@pbx:~# cat /proc/mdstat
Personalities : [raid1] 
md2 : active raid1 sda6[0] sdb6[2](F)
      1174516 blocks super 1.2 [2/1] [U_]
      
md1 : active raid1 sda5[0] sdb5[2](F)
      877927288 blocks super 1.2 [2/1] [U_]
      
md0 : active raid1 sda1[0] sdb1[2](F)
      97653688 blocks super 1.2 [2/1] [U_]
      
unused devices: <none>
</code>

Odebrani vadneho disku z raidu:
<code>
root@pbx:~# mdadm --manage /dev/md0 --remove /dev/sdb1
mdadm: hot removed /dev/sdb1 from /dev/md0
root@pbx:~#
root@pbx:~# mdadm --manage /dev/md1 --remove /dev/sdb5
mdadm: hot removed /dev/sdb5 from /dev/md1
root@pbx:~#
root@pbx:~# mdadm --manage /dev/md2 --remove /dev/sdb6
mdadm: hot removed /dev/sdb6 from /dev/md2
</code>

**Výměna disku:**
  * Vypnout server
  * Vyměnit disk
  * Zapnout server

**Zkopirovani partition table (z sda) na nový disk (sdb):**
<code>
root@pbx:~# sfdisk -d /dev/sda | sfdisk /dev/sdb
root@pbx:~# fdisk -l
</code>

**Přidání partition do raidu:**
<code>
mdadm --manage /dev/md0 --add /dev/sdb1
mdadm --manage /dev/md1 --add /dev/sdb5
mdadm --manage /dev/md2 --add /dev/sdb6
</code>

**Kontrola:**
<code>
cat /proc/mdstat
</code>

===== Zrušení RAIDu =====
<code>
mdadm --stop /dev/md125
mdadm --remove /dev/md125
</code>