Raid:Manual Rebuild
SME Servers Raid Options are largely automated, if you built your system with a single hard disk simply logon as admin and select Disk Redundancy to add a new drive to your RAID1 array. The same procedure is used if you have a disk failure in a RAID array and you have replaced that failed disk.
But with the best laid plans things don't always go according to plan, these are the processes required to do it manually.
See also: Hard Disk Partitioning and Raid#Resynchronising_a_Failed_RAID
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
You can refer to this page for more information how activate or understand the Analysis and Reporting Technology (SMART) Monitor_Disk_Health
[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
- dd
[root@ ~]# dd if=/dev/sda1 of=/dev/sdb1
- grub
[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 (hd1) /dev/sdb grub> root (hd1,0) Filesystem type is ext2fs, partition type 0xfd grub> setup (hd1) 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 (hd1) (hd1)1+16 p (hd1,0)/grub/stage2 /grub/grub.conf"... succeeded Done. grub> quit