How To Set Up Software RAID1 On A Running LVM System (Incl. GRUB2 Configuration) (Debian Squeeze) - 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
root@server1:~# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/server1-root
4.5G 722M 3.6G 17% /
tmpfs 249M 0 249M 0% /lib/init/rw
udev 244M 128K 244M 1% /dev
tmpfs 249M 0 249M 0% /dev/shm
/dev/md0 236M 18M 206M 8% /boot
root@server1:~#
The output of
cat /proc/mdstat
should be as follows:
root@server1:~# cat /proc/mdstat
Personalities : [raid1]
md1 : active raid1 sda5[2] sdb5[1]
4989940 blocks super 1.2 [2/2] [UU]
md0 : active raid1 sdb1[1]
248820 blocks super 1.2 [2/1] [_U]
unused devices: <none>
root@server1:~#
The outputs of pvdisplay, vgdisplay, and lvdisplay should be as follows:
pvdisplay
root@server1:~# pvdisplay
--- Physical volume ---
PV Name /dev/md1
VG Name server1
PV Size 4.76 GiB / not usable 1012.00 KiB
Allocatable yes (but full)
PE Size 4.00 MiB
Total PE 1218
Free PE 0
Allocated PE 1218
PV UUID W4I07I-RT3P-DK1k-1HBz-oJvp-6in0-uQ53KS
root@server1:~#
vgdisplay
root@server1:~# 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 1218 / 4.76 GiB
Free PE / Size 0 / 0
VG UUID m99fJX-gMl9-g2XZ-CazH-32s8-sy1Q-8JjCUW
root@server1:~#
lvdisplay
root@server1:~# lvdisplay
--- Logical volume ---
LV Name /dev/server1/root
VG Name server1
LV UUID 8SNLPE-gHqA-a2LX-BO9o-0QQO-DV2z-3WvTYe
LV Write Access read/write
LV Status available
# open 1
LV Size 4.51 GiB
Current LE 1155
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 256
Block device 253:0
--- Logical volume ---
LV Name /dev/server1/swap_1
VG Name server1
LV UUID kYaKtb-vkkV-TDDE-me1R-nnER-dzN8-BcVTwz
LV Write Access read/write
LV Status available
# open 1
LV Size 252.00 MiB
Current LE 63
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 256
Block device 253:1
root@server1:~#
Now we must change the partition type of /dev/sda1 to Linux raid autodetect as well:
fdisk /dev/sda
root@server1:~# 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.
root@server1:~#
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
root@server1:~# cat /proc/mdstat
Personalities : [raid1]
md1 : active raid1 sda5[2] sdb5[1]
4989940 blocks super 1.2 [2/2] [UU]
md0 : active raid1 sda1[2] sdb1[1]
248820 blocks super 1.2 [2/2] [UU]
unused devices: <none>
root@server1:~#
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, 24 May 2011 21:11:37 +0200 # by mkconf 3.1.4-1+8efb9d1 ARRAY /dev/md/0 metadata=1.2 UUID=6cde4bf4:7ee67d24:b31e2713:18865f31 name=server1.example.com:0 ARRAY /dev/md/1 metadata=1.2 UUID=3ce9f2f2:ac89f75a:530c5ee9:0d4c67da 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
Now if you take a look at /boot/grub/grub.cfg, you should find that the menuentry stanzas in the ### BEGIN /etc/grub.d/10_linux ### section look pretty much the same as what we had in /etc/grub.d/09_swraid1_setup (they should now also be set to boot from /dev/md0 instead of (hd0) or (hd1)), that's why we don't need /etc/grub.d/09_swraid1_setup anymore.
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!
