Difference between revisions of "Talk:Raid:Manual Rebuild"

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Please see my remarks at [[User_talk:Davidbray]] <small>—&nbsp;[[User:Cactus|Cactus]] ([[User talk:Cactus|talk]]&nbsp;|&nbsp;[[Special:Contributions/Cactus|contribs]])&nbsp;</small> 16:48, 19 March 2010 (UTC)
 
  
Thanks Cactus - I've made some changes here so look forward to your feedback
 
 
===HowTo: Write the GRUB boot sector===
 
[[User:Trex|Trex]] ([[User talk:Trex|talk]]) 00:26, 5 February 2013 (MST) Should add a note as per the comment 24 in this Bug re grub will not install on an unpartioned disk
 
 
[[User:Stephdl|Stephdl]] ([[User talk:Stephdl|talk]]) 12:24, 6 February 2013 (MST) ok i work on the howTo...work in progress, don't disturb :p
 
 
 
 
 
== HowTo: Remove a disk from the RAID1 Array from the command Line ==
 
 
=== Look at the mdstat ===
 
 
First we must determine which drive is in default.
 
 
 
[root@sme8-64-dev ~]# cat /proc/mdstat
 
Personalities : [raid1]
 
md1 : active raid1 sdb1[1] sda1[0]
 
      104320 blocks [2/2] [UU]
 
     
 
md2 : active raid1 sdb2[2](F) sda2[0]
 
      52323584 blocks [2/1] [U_]
 
     
 
unused devices: <none>
 
 
(S)= Spare
 
(F)= Fail
 
[0]= number of the disk
 
 
{{note box|As we can see the partition sdb2 is in default, we can see the flag: sdb2 [2] (F). We need to resynchronize the disk sdb to the existing array md2.}}
 
 
=== Fail and remove the disk, '''sdb''' in this case ===
 
 
[root@ ~]# '''mdadm --manage /dev/md2 --fail /dev/sdb2'''
 
mdadm: set /dev/sdb2 faulty in /dev/md2
 
[root@ ~]# '''mdadm --manage /dev/md2 --remove /dev/sdb2'''
 
mdadm: hot removed /dev/sdb2
 
[root@ ~]# '''mdadm --manage /dev/md1 --fail /dev/sdb1'''
 
mdadm: set /dev/sdb1 faulty in /dev/md1
 
[root@ ~]# '''mdadm --manage /dev/md1 --remove /dev/sdb1'''
 
mdadm: hot removed /dev/sdb1
 
 
=== Do your Disk Maintenance here ===
 
 
At this point the disk is idle.
 
 
[root@sme8-64-dev ~]# cat /proc/mdstat
 
Personalities : [raid1]
 
md1 : active raid1 sda1[0]
 
      104320 blocks [2/1] [U_]
 
     
 
md2 : active raid1 sda2[0]
 
      52323584 blocks [2/1] [U_]
 
     
 
unused devices: <none>
 
 
{{note box|You'll have to determine if your disk can be reinstated at the array. In fact sometimes a raid can get out of sync after a power failure but also some outages times for physical disk itself. It is necessary to test the hard drive if this occurs repeatedly. For this we will use '''smartctl'''.}}
 
 
For all the details available by SMART on the disk
 
 
smartctl -a /dev/sdb
 
 
At least two types of tests are possible, short (~ 1 min) and long (~ 10 min to 90 min).
 
 
smartctl -t short /dev/sdb #short test
 
smartctl -t long  /dev/sdb #long test
 
 
to access the results / statistics for these tests:
 
 
smartctl -l selftest /dev/sdb
 
 
{{Note box|if you need to change the disk due to physical failure found by the smartctl command, install a new disk of the same capacity (or more) and enter the following commands to recreate new partitions by copying them from healthy disk sda.}}
 
 
sfdisk -d /dev/sda > sfdisk_sda.output
 
sfdisk /dev/sdb < sfdisk_sda.output
 
 
If you want to reintegrate the same disk without replacing it, go to the next step.
 
 
=== Add the partitions back ===
 
 
[root@ ~]# '''mdadm --manage /dev/md1 --add /dev/sdb1'''
 
mdadm: hot added /dev/sdb1
 
[root@ ~]# '''mdadm --manage /dev/md2 --add /dev/sdb2'''
 
mdadm: hot added /dev/sdb2
 
 
=== Another Look at the mdstat ===
 
 
[root@sme8-64-dev ~]# cat /proc/mdstat
 
Personalities : [raid1]
 
md1 : active raid1 sdb1[1] sda1[0]
 
      104320 blocks [2/2] [UU]
 
     
 
md2 : active raid1 sdb2[2] sda2[0]
 
      52323584 blocks [2/1] [U_]
 
      [>....................]  recovery =  1.9% (1041600/52323584) finish=14.7min speed=57866K/sec
 
 
unused devices: <none>
 

Latest revision as of 02:35, 8 February 2013