Cloning raid1 boot disks: Difference between revisions
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Latest revision as of 16:02, 16 September 2015
Cloning raid1 boot disks
- starting point:
- fdisk -l
[root@deap02 ~]# fdisk -l Disk /dev/sda: 16.0 GB, 16013852672 bytes 224 heads, 56 sectors/track, 2493 cylinders Units = cylinders of 12544 * 512 = 6422528 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x0007e9b2 Device Boot Start End Blocks Id System /dev/sda1 * 1 2493 15636068 fd Linux raid autodetect Disk /dev/md0: 16.0 GB, 16011259904 bytes 2 heads, 4 sectors/track, 3908999 cylinders Units = cylinders of 8 * 512 = 4096 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000 Disk /dev/md0 doesn't contain a valid partition table Disk /dev/sdb: 16.0 GB, 16013852672 bytes 224 heads, 56 sectors/track, 2493 cylinders Units = cylinders of 12544 * 512 = 6422528 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0xeccedcd8 Device Boot Start End Blocks Id System /dev/sdb1 * 1 2493 15636068 fd Linux raid autodetect
- cat /proc/mdstat
[root@deap02 ~]# cat /proc/mdstat
Personalities : [raid1]
md0 : active raid1 sdb1[2] sda1[1]
15635996 blocks super 1.0 [2/2] [UU]
bitmap: 1/1 pages [4KB], 65536KB chunk
unused devices: <none>
- disconnect one of the 2 boot disks
- connect a new blank disk
- fdisk -l ### to see which /dev/sdX device it will be
- fdisk -H224 -S56 /dev/sdX
- for 8/16GB USB disk: create one partition spanning the whole device, type 0xfd, set "active/bootable" flag
- for SSD or high capacity disk: omit the -H and -S flags, create partitions 1 and 2 to match the boot and swap partitions on the active boot disk
- result should look like this:
Disk /dev/sdb: 16.0 GB, 16013852672 bytes 224 heads, 56 sectors/track, 2493 cylinders Units = cylinders of 12544 * 512 = 6422528 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0xeccedcd8 Device Boot Start End Blocks Id System /dev/sdb1 * 1 2493 15636068 fd Linux raid autodetect
- mdadm --add /dev/md0 /dev/sdX1
- cat /proc/mdstat ### should look like this:
[root@deap02 ~]# cat /proc/mdstat
Personalities : [raid1]
md0 : active raid1 sdb1[2] sda1[1]
15635996 blocks super 1.0 [2/1] [_U]
[>....................] recovery = 0.5% (92288/15635996) finish=14.0min speed=18457K/sec
bitmap: 1/1 pages [4KB], 65536KB chunk
unused devices: <none>
- wait until raid1 resync completes: watch -d -n1 "cat /proc/mdstat" or watch the grass grow
- cat /proc/mdstat ### should look like this:
[root@deap02 ~]# cat /proc/mdstat
Personalities : [raid1]
md0 : active raid1 sdb1[2] sda1[1]
15635996 blocks super 1.0 [2/2] [UU]
bitmap: 1/1 pages [4KB], 65536KB chunk
unused devices: <none>
- install GRUB on new disks: (remember to substitute /dev/sdX !!!) (do NOT change (hd0) to (hd1), etc !!!)
- echo -e "device (hd0) /dev/sdX\nroot (hd0,0)\nsetup (hd0)\n" | grub --batch --no-floppy
- sync; sync; sync
- done