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| − | Please see my remarks at [[User_talk:Davidbray]] <small>— [[User:Cactus|Cactus]] ([[User talk:Cactus|talk]] | [[Special:Contributions/Cactus|contribs]]) </small> 16:48, 19 March 2010 (UTC)
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| − | Thanks Cactus - I've made some changes here so look forward to your feedback
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| − | ===HowTo: Write the GRUB boot sector===
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| − | [[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
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| − | [[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
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| − | == HowTo: Reinstate a disk from the RAID1 Array with the command Line ==
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| − | === Look at the mdstat ===
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| − | First we must determine which drive is in default.
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| − | [root@ ~]#'''cat /proc/mdstat'''
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| − | Personalities : [raid1]
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| − | md1 : active raid1 sdb1[1] sda1[0]
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| − | 104320 blocks [2/2] [UU]
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| − | md2 : active raid1 sdb2[2](F) sda2[0]
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| − | 52323584 blocks [2/1] [U_]
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| − | unused devices: <none>
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| − | (S)= Spare
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| − | (F)= Fail
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| − | [0]= number of the disk
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| − | {{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.}}
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| − | === Fail and remove the disk, '''sdb''' in this case ===
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| − | [root@ ~]# '''mdadm --manage /dev/md2 --fail /dev/sdb2'''
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| − | mdadm: set /dev/sdb2 faulty in /dev/md2
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| − | [root@ ~]# '''mdadm --manage /dev/md2 --remove /dev/sdb2'''
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| − | mdadm: hot removed /dev/sdb2
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| − | [root@ ~]# '''mdadm --manage /dev/md1 --fail /dev/sdb1'''
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| − | mdadm: set /dev/sdb1 faulty in /dev/md1
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| − | [root@ ~]# '''mdadm --manage /dev/md1 --remove /dev/sdb1'''
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| − | mdadm: hot removed /dev/sdb1
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| − | === Do your Disk Maintenance here ===
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| − | At this point the disk is idle.
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| − | [root@ ~]# '''cat /proc/mdstat'''
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| − | Personalities : [raid1]
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| − | md1 : active raid1 sda1[0]
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| − | 104320 blocks [2/1] [U_]
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| − | md2 : active raid1 sda2[0]
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| − | 52323584 blocks [2/1] [U_]
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| − | unused devices: <none>
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| − | {{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'''.}}
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| − | For all the details available by SMART on the disk
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| − | [root@ ~]#'''smartctl -a /dev/sdb'''
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| − | At least two types of tests are possible, short (~ 1 min) and long (~ 10 min to 90 min).
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| − | [root@ ~]#'''smartctl -t short /dev/sdb''' #short test
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| − | [root@ ~]# '''smartctl -t long /dev/sdb''' #long test
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| − | to access the results / statistics for these tests:
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| − | [root@ ~]#'''smartctl -l selftest /dev/sdb'''
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| − | {{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.}}
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| − | [root@ ~]#sfdisk -d /dev/sda > sfdisk_sda.output
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| − | [root@ ~]#sfdisk /dev/sdb < sfdisk_sda.output
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| − | If you want to reinstate the same disk without replacing it, go to the next step.
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| − | === Add the partitions back ===
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| − | [root@ ~]# '''mdadm --manage /dev/md1 --add /dev/sdb1'''
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| − | mdadm: hot added /dev/sdb1
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| − | [root@ ~]# '''mdadm --manage /dev/md2 --add /dev/sdb2'''
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| − | mdadm: hot added /dev/sdb2
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| − | === Another Look at the mdstat ===
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| − | [root@sme8-64-dev ~]# cat /proc/mdstat
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| − | Personalities : [raid1]
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| − | md1 : active raid1 sdb1[1] sda1[0]
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| − | 104320 blocks [2/2] [UU]
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| − | md2 : active raid1 sdb2[2] sda2[0]
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| − | 52323584 blocks [2/1] [U_]
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| − | [>....................] recovery = 1.9% (1041600/52323584) finish=14.7min speed=57866K/sec
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| − | unused devices: <none>
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| − | {{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. }}
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| − | == HowTo: Write the GRUB boot sector ==
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| − | [root@ ~]# '''grub'''
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| − | GNU GRUB version 0.95 (640K lower / 3072K upper memory)
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| − | [ Minimal BASH-like line editing is supported. For the first word, TAB
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| − | lists possible command completions. Anywhere else TAB lists the possible
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| − | completions of a device/filename.]
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| − | grub> '''device (hd0) /dev/sdb'''
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| − | grub> '''root (hd0,0)'''
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| − | Filesystem type is ext2fs, partition type 0xfd
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| − | grub> '''setup (hd0)'''
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| − | Checking if "/boot/grub/stage1" exists... no
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| − | Checking if "/grub/stage1" exists... yes
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| − | Checking if "/grub/stage2" exists... yes
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| − | Checking if "/grub/e2fs_stage1_5" exists... yes
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| − | Running "embed /grub/e2fs_stage1_5 (hd0)"... 16 sectors are embedded.
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| − | succeeded
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| − | Running "install /grub/stage1 (hd0) (hd0)1+16 p (hd0,0)/grub/stage2 /grub/grub.conf"... succeeded
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| − | Done.
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| − | grub> '''quit'''
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