How To Set Up Software RAID1 On A Running LVM System (Incl. GRUB2 Configuration) (Ubuntu 10.04) - 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
4.5G 816M 3.4G 19% /
none 242M 196K 242M 1% /dev
none 247M 0 247M 0% /dev/shm
none 247M 40K 247M 1% /var/run
none 247M 0 247M 0% /var/lock
none 247M 0 247M 0% /lib/init/rw
/dev/md0 236M 23M 201M 11% /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]
248768 blocks [2/1] [_U]
md1 : active raid1 sda5[0] sdb5[1]
4990912 blocks [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 1.94 MiB
Allocatable yes
PE Size 4.00 MiB
Total PE 1218
Free PE 3
Allocated PE 1215
PV UUID rQf0Rj-Nn9l-VgbP-0kIr-2lve-5jlC-TWTBGp
[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 hMwXAh-zZsA-w39k-g6Bg-LW4W-XX8q-EbyXfA
[email protected]:~#
lvdisplay
[email protected]:~# lvdisplay
--- Logical volume ---
LV Name /dev/server1/root
VG Name server1
LV UUID b5A1R5-Zhml-LSNy-v7WY-NVmD-yX1w-tuQVUW
LV Write Access read/write
LV Status available
# open 1
LV Size 4.49 GiB
Current LE 1149
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 256
Block device 251:0
--- Logical volume ---
LV Name /dev/server1/swap_1
VG Name server1
LV UUID 2UuF7C-zxKA-Hgz1-gZHe-rFlq-cKW7-jYVCzp
LV Write Access read/write
LV Status available
# open 1
LV Size 264.00 MiB
Current LE 66
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 256
Block device 251:1
[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[0] sdb1[1]
248768 blocks [2/2] [UU]
md1 : active raid1 sda5[0] sdb5[1]
4990912 blocks [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 Wed, 16 Jun 2010 20:01:25 +0200 # by mkconf $Id$ ARRAY /dev/md0 level=raid1 num-devices=2 UUID=90f05e41:bf936896:325ecf68:79913751 ARRAY /dev/md1 level=raid1 num-devices=2 UUID=1ab36b7f:3e2031c0:325ecf68:79913751 |
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 (hd0,1) or (hd1,1)), that's why we don't need /etc/grub.d/09_swraid1_setup anymore.
Reboot the system:
reboot
It should boot without problems.
That's it - you've successfully set up software RAID1 on your running LVM system!
