How To Set Up Software RAID1 On A Running LVM System (Incl. GRUB2 Configuration) (Ubuntu 11.10) - Page 3
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6 Preparing GRUB2
Afterwards we must make sure that the GRUB2 bootloader is installed on both hard drives, /dev/sda and /dev/sdb:
grub-install /dev/sda
grub-install /dev/sdb
Now we reboot the system and hope that it boots ok from our RAID arrays:
reboot
7 Preparing /dev/sda
If all goes well, you should now find /dev/md0 in the output of
df -h
[email protected]:~# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/server1-root
4.2G 1002M 3.0G 25% /
udev 238M 8.0K 238M 1% /dev
tmpfs 99M 240K 99M 1% /run
none 5.0M 0 5.0M 0% /run/lock
none 247M 0 247M 0% /run/shm
/dev/md0 236M 26M 198M 12% /boot
[email protected]:~#
The output of
cat /proc/mdstat
should be as follows:
[email protected]:~# cat /proc/mdstat
Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10]
md0 : active raid1 sdb1[1]
248820 blocks super 1.2 [2/1] [_U]
md1 : active raid1 sda5[2] sdb5[1]
4989940 blocks super 1.2 [2/2] [UU]
unused devices: <none>
[email protected]:~#
The outputs of pvdisplay, vgdisplay, and lvdisplay should be as follows:
pvdisplay
[email protected]:~# pvdisplay
--- Physical volume ---
PV Name /dev/md1
VG Name server1
PV Size 4.76 GiB / not usable 1012.00 KiB
Allocatable yes
PE Size 4.00 MiB
Total PE 1218
Free PE 3
Allocated PE 1215
PV UUID w1Mg12-OHEj-paLg-9xyJ-jQuU-cQHT-p2qVKf
[email protected]:~#
vgdisplay
[email protected]:~# vgdisplay
--- Volume group ---
VG Name server1
System ID
Format lvm2
Metadata Areas 1
Metadata Sequence No 9
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 2
Open LV 2
Max PV 0
Cur PV 1
Act PV 1
VG Size 4.76 GiB
PE Size 4.00 MiB
Total PE 1218
Alloc PE / Size 1215 / 4.75 GiB
Free PE / Size 3 / 12.00 MiB
VG UUID kwDyrp-sFA7-3s3i-FVWc-AGck-NX6H-yo4Pyt
[email protected]:~#
lvdisplay
[email protected]:~# lvdisplay
--- Logical volume ---
LV Name /dev/server1/root
VG Name server1
LV UUID dNn3NY-YhPm-qE8r-Dr8L-k8CG-ECLp-YjRnGf
LV Write Access read/write
LV Status available
# open 1
LV Size 4.25 GiB
Current LE 1088
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 256
Block device 252:0
--- Logical volume ---
LV Name /dev/server1/swap_1
VG Name server1
LV UUID HKIiwv-7X8Y-rzeg-aedK-5RZo-g3Km-QjxkdL
LV Write Access read/write
LV Status available
# open 2
LV Size 508.00 MiB
Current LE 127
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 256
Block device 252:1
[email protected]:~#
Now we must change the partition type of /dev/sda1 to Linux raid autodetect as well:
fdisk /dev/sda
[email protected]:~# fdisk /dev/sda
WARNING: DOS-compatible mode is deprecated. It's strongly recommended to
switch off the mode (command 'c') and change display units to
sectors (command 'u').
Command (m for help): <-- t
Partition number (1-5): <-- 1
Hex code (type L to list codes): <-- fd
Changed system type of partition 1 to fd (Linux raid autodetect)
Command (m for help): <-- w
The partition table has been altered!
Calling ioctl() to re-read partition table.
WARNING: Re-reading the partition table failed with error 16: Device or resource busy.
The kernel still uses the old table. The new table will be used at
the next reboot or after you run partprobe(8) or kpartx(8)
Syncing disks.
[email protected]:~#
Now we can add /dev/sda1 to the /dev/md0 RAID array:
mdadm --add /dev/md0 /dev/sda1
Now take a look at
cat /proc/mdstat
[email protected]:~# cat /proc/mdstat
Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10]
md0 : active raid1 sda1[2] sdb1[1]
248820 blocks super 1.2 [2/2] [UU]
md1 : active raid1 sda5[2] sdb5[1]
4989940 blocks super 1.2 [2/2] [UU]
unused devices: <none>
[email protected]:~#
Then adjust /etc/mdadm/mdadm.conf to the new situation:
cp /etc/mdadm/mdadm.conf_orig /etc/mdadm/mdadm.conf
mdadm --examine --scan >> /etc/mdadm/mdadm.conf
/etc/mdadm/mdadm.conf should now look something like this:
cat /etc/mdadm/mdadm.conf
# mdadm.conf # # Please refer to mdadm.conf(5) for information about this file. # # by default, scan all partitions (/proc/partitions) for MD superblocks. # alternatively, specify devices to scan, using wildcards if desired. DEVICE partitions # auto-create devices with Debian standard permissions CREATE owner=root group=disk mode=0660 auto=yes # automatically tag new arrays as belonging to the local system HOMEHOST <system> # instruct the monitoring daemon where to send mail alerts MAILADDR root # definitions of existing MD arrays # This file was auto-generated on Tue, 20 Mar 2012 15:40:06 +0100 # by mkconf $Id$ ARRAY /dev/md/0 metadata=1.2 UUID=2d5659ba:1978bfac:40d0b815:229d3382 name=server1.example.com:0 ARRAY /dev/md/1 metadata=1.2 UUID=3c524dfa:445bb555:b4d039e9:b39553e1 name=server1.example.com:1 |
Now we delete /etc/grub.d/09_swraid1_setup...
rm -f /etc/grub.d/09_swraid1_setup
... and update our GRUB2 bootloader configuration:
update-grub
update-initramfs -u
Afterwards we must make sure that the GRUB2 bootloader is installed on both hard drives, /dev/sda and /dev/sdb:
grub-install /dev/sda
grub-install /dev/sdb
Reboot the system:
reboot
It should boot without problems.
That's it - you've successfully set up software RAID1 on your running LVM system!
