Difference between revisions of "Raid:Manual Rebuild"
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unused devices: <none> | unused devices: <none> | ||
| − | == | + | == HowTo: Reinstate a disk from the RAID1 Array with the command Line == |
| − | + | === Look at the mdstat === | |
| − | + | First we must determine which drive is in default. | |
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| − | + | [root@ ~]#'''cat /proc/mdstat''' | |
| − | + | Personalities : [raid1] | |
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| − | [root@ ~]# '''cat /proc/mdstat''' | ||
| − | Personalities : [raid1] | ||
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md1 : active raid1 sdb1[1] sda1[0] | md1 : active raid1 sdb1[1] sda1[0] | ||
104320 blocks [2/2] [UU] | 104320 blocks [2/2] [UU] | ||
| − | + | ||
| + | md2 : active raid1 sdb2[2](F) sda2[0] | ||
| + | 52323584 blocks [2/1] [U_] | ||
| + | |||
unused devices: <none> | 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 === | === Fail and remove the disk, '''sdb''' in this case === | ||
| Line 120: | Line 58: | ||
=== Do your Disk Maintenance here === | === Do your Disk Maintenance here === | ||
| − | At this point the disk is idle, | + | At this point the disk is idle. |
| + | |||
| + | [root@ ~]# '''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 times for physical outages of the hard disk. It is necessary to test the hard disk if this occurs repeatedly. For this we will use '''smartctl'''.}} | ||
| + | |||
| + | For all the details available by SMART on the disk | ||
| + | |||
| + | [root@ ~]# '''smartctl -a /dev/sdb''' | ||
| + | |||
| + | At least two types of tests are possible, short (~ 1 min) and long (~ 10 min to 90 min). | ||
| + | |||
| + | [root@ ~]# '''smartctl -t short /dev/sdb''' #short test | ||
| + | [root@ ~]# '''smartctl -t long /dev/sdb''' #long test | ||
| + | |||
| + | to access the results / statistics for these tests: | ||
| + | |||
| + | [root@ ~]# '''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.}} | ||
| + | |||
| + | [root@ ~]# '''sfdisk -d /dev/sda > sfdisk_sda.output''' | ||
| + | [root@ ~]# '''sfdisk /dev/sdb < sfdisk_sda.output''' | ||
| + | |||
| + | If you want to reinstate the same disk without replacing it, go to the next step. | ||
=== Add the partitions back === | === Add the partitions back === | ||
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=== Another Look at the mdstat === | === Another Look at the mdstat === | ||
| − | [root@ ~]# | + | [root@sme8-64-dev ~]# cat /proc/mdstat |
| − | Personalities : [raid1] | + | Personalities : [raid1] |
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md1 : active raid1 sdb1[1] sda1[0] | md1 : active raid1 sdb1[1] sda1[0] | ||
104320 blocks [2/2] [UU] | 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> | unused devices: <none> | ||
| − | + | {{note box|with a new disk it may be worthwhile to reinstall grub to avoid problems on startup error. The grub is the program that allows you to launch the operating systems.please enter the following commands. }} | |
| − | == | + | == HowTo: Write the GRUB boot sector == |
| − | [root@ ~]# ''' | + | [root@ ~]# '''dd if=/dev/sda1 of=/dev/sdb1''' |
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[root@ ~]# '''grub''' | [root@ ~]# '''grub''' | ||
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grub> '''quit''' | grub> '''quit''' | ||
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<noinclude>[[Category:Howto]][[Category:Administration:Storage]]</noinclude> | <noinclude>[[Category:Howto]][[Category:Administration:Storage]]</noinclude> | ||
Revision as of 02:34, 8 February 2013
Raid: Manual Rebuild
SME Servers Raid Options are largely automated, if you built your system with a single hard disk, or have a hard disk failure, simply logon as admin and select Disk Redundancy to add a new drive to your RAID1 array.
But with the best laid plans things don't always goaccording to plan, these are the processes required to do it manually
HowTo: Manage/Check a RAID1 Array from the command Line
What is the Status of the Array
[root@ ~]# cat /proc/mdstat
Personalities : [raid1]
md2 : active raid1 sdb2[2] sda2[0]
488279488 blocks [2/1] [U_]
[=>...................] recovery = 6.3% (31179264/488279488) finish=91.3min speed=83358K/sec
md1 : active raid1 sdb1[1] sda1[0]
104320 blocks [2/2] [UU]
unused devices: <none>
HowTo: Reinstate a disk from the RAID1 Array with the command Line
Look at the mdstat
First we must determine which drive is in default.
[root@ ~]#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
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@ ~]# 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>
For all the details available by SMART on the disk
[root@ ~]# smartctl -a /dev/sdb
At least two types of tests are possible, short (~ 1 min) and long (~ 10 min to 90 min).
[root@ ~]# smartctl -t short /dev/sdb #short test [root@ ~]# smartctl -t long /dev/sdb #long test
to access the results / statistics for these tests:
[root@ ~]# smartctl -l selftest /dev/sdb
[root@ ~]# sfdisk -d /dev/sda > sfdisk_sda.output [root@ ~]# sfdisk /dev/sdb < sfdisk_sda.output
If you want to reinstate 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>
HowTo: Write the GRUB boot sector
[root@ ~]# dd if=/dev/sda1 of=/dev/sdb1
[root@ ~]# grub
GNU GRUB version 0.95 (640K lower / 3072K upper memory)
[ Minimal BASH-like line editing is supported. For the first word, TAB
lists possible command completions. Anywhere else TAB lists the possible
completions of a device/filename.]
grub> device (hd0) /dev/sdb
grub> root (hd0,0)
Filesystem type is ext2fs, partition type 0xfd
grub> setup (hd0)
Checking if "/boot/grub/stage1" exists... no
Checking if "/grub/stage1" exists... yes
Checking if "/grub/stage2" exists... yes
Checking if "/grub/e2fs_stage1_5" exists... yes
Running "embed /grub/e2fs_stage1_5 (hd0)"... 16 sectors are embedded.
succeeded
Running "install /grub/stage1 (hd0) (hd0)1+16 p (hd0,0)/grub/stage2 /grub/grub.conf"... succeeded
Done.
grub> quit
