Setting Up Network RAID1 With DRBD On Ubuntu 11.10
Version 1.0
Author: Falko Timme
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This tutorial shows how to set up network RAID1 with the help of DRBD on two Ubuntu 11.10 systems. DRBD stands for Distributed Replicated Block Device and allows you to mirror block devices over a network. This is useful for high-availability setups (like a HA NFS server) because if one node fails, all data is still available from the other node.
I do not issue any guarantee that this will work for you!
1 Preliminary Note
I will use two servers here (both running Ubuntu 11.10):
- server1.example.com (IP address 192.168.0.100)
- server2.example.com (IP address: 192.168.0.101)
Both nodes have an unpartitioned second drive (/dev/sdb) with identical size (30GB in this example) that I want to mirror over the network (network RAID1) with the help of DRBD.
It is important that both nodes can resolve each other, either through DNS or through /etc/hosts. If you did not create DNS records for server1.example.com and server2.example.com, you can modify /etc/hosts on both nodes as follows:
server1/server2:
vi /etc/hosts
127.0.0.1 localhost.localdomain localhost 192.168.0.100 server1.example.com server1 192.168.0.101 server2.example.com server2 # The following lines are desirable for IPv6 capable hosts ::1 ip6-localhost ip6-loopback fe00::0 ip6-localnet ff00::0 ip6-mcastprefix ff02::1 ip6-allnodes ff02::2 ip6-allrouters |
I'm running all the steps in this tutorial with root privileges, so make sure you're logged in as root:
sudo su
2 Synchronize Time
server1/server2:
It is very important that both nodes have the same time. Therefore we install the ntp packages:
apt-get install ntp ntpdate
3 Partition /dev/sdb
server1/server2:
Right now, our partitioning looks as follows:
fdisk -l
root@server1:~# fdisk -l
Disk /dev/sda: 32.2 GB, 32212254720 bytes
255 heads, 63 sectors/track, 3916 cylinders, total 62914560 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x000712c1
Device Boot Start End Blocks Id System
/dev/sda1 * 2048 499711 248832 83 Linux
/dev/sda2 501758 62912511 31205377 5 Extended
/dev/sda5 501760 62912511 31205376 8e Linux LVM
Disk /dev/sdb: 32.2 GB, 32212254720 bytes
255 heads, 63 sectors/track, 3916 cylinders, total 62914560 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000
Disk /dev/sdb doesn't contain a valid partition table
Disk /dev/mapper/server1-root: 31.4 GB, 31415336960 bytes
255 heads, 63 sectors/track, 3819 cylinders, total 61358080 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000
Disk /dev/mapper/server1-root doesn't contain a valid partition table
Disk /dev/mapper/server1-swap_1: 536 MB, 536870912 bytes
255 heads, 63 sectors/track, 65 cylinders, total 1048576 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000
Disk /dev/mapper/server1-swap_1 doesn't contain a valid partition table
root@server1:~#
As you see, /dev/sdb is not partitioned. We change that now and create one big partition on it, /dev/sdb1:
fdisk /dev/sdb
root@server1:~# fdisk /dev/sdb
Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel
Building a new DOS disklabel with disk identifier 0xf7ab5969.
Changes will remain in memory only, until you decide to write them.
After that, of course, the previous content won't be recoverable.
Warning: invalid flag 0x0000 of partition table 4 will be corrected by w(rite)
Command (m for help): <-- n
Command action
e extended
p primary partition (1-4)
<-- p
Partition number (1-4, default 1): <-- 1
First sector (2048-62914559, default 2048): <-- ENTER
Using default value 2048
Last sector, +sectors or +size{K,M,G} (2048-62914559, default 62914559): <-- ENTER
Using default value 62914559
Command (m for help): <-- t
Selected partition 1
Hex code (type L to list codes): <-- 83
Command (m for help): <-- w
The partition table has been altered!
Calling ioctl() to re-read partition table.
Syncing disks.
root@server1:~#
Now run
fdisk -l
again, and you should find /dev/sdb1 in the output:
root@server1:~# fdisk -l
Disk /dev/sda: 32.2 GB, 32212254720 bytes
255 heads, 63 sectors/track, 3916 cylinders, total 62914560 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x000712c1
Device Boot Start End Blocks Id System
/dev/sda1 * 2048 499711 248832 83 Linux
/dev/sda2 501758 62912511 31205377 5 Extended
/dev/sda5 501760 62912511 31205376 8e Linux LVM
Disk /dev/sdb: 32.2 GB, 32212254720 bytes
64 heads, 51 sectors/track, 19275 cylinders, total 62914560 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0xf7ab5969
Device Boot Start End Blocks Id System
/dev/sdb1 2048 62914559 31456256 83 Linux
Disk /dev/mapper/server1-root: 31.4 GB, 31415336960 bytes
255 heads, 63 sectors/track, 3819 cylinders, total 61358080 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000
Disk /dev/mapper/server1-root doesn't contain a valid partition table
Disk /dev/mapper/server1-swap_1: 536 MB, 536870912 bytes
255 heads, 63 sectors/track, 65 cylinders, total 1048576 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000
Disk /dev/mapper/server1-swap_1 doesn't contain a valid partition table
root@server1:~#
