DRBD Quickstart

Install It

Centos 5:

yum install kmod-drbd83

Ubuntu 10.04:

apt-get install drbd8-utils drbdlinks

The Config File

global {
  usage-count yes;
}
common {
  protocol C;
}
resource r0 {
  on alice {
    device    /dev/drbd1;
    disk      /dev/sda7;
    address   10.1.1.31:7789;
    meta-disk internal;
  }
  on bob {
    device    /dev/drbd1;
    disk      /dev/sda7;
    address   10.1.1.32:7789;
    meta-disk internal;
  }
}

Initial Initialization

First create the metadata, based on the resource name. Do this on both nodes

drbdadm create-md resource

Now startup drbd to connect the two. Do this on both nodes:

/etc/init.d/drbd start

Check out the status of drbd:

cat /proc/drbd
version: 8.3.0 (api:88/proto:86-89)
GIT-hash: 9ba8b93e24d842f0dd3fb1f9b90e8348ddb95829 build by buildsystem@linbit, 2008-12-18 16:02:26
 1: cs:Connected ro:Secondary/Secondary ds:Inconsistent/Inconsistent C r---
    ns:0 nr:0 dw:0 dr:0 al:0 bm:0 lo:0 pe:0 ua:0 ap:0 ep:1 wo:b oos:200768

Notice that they are both secondary, and their data is inconsistent. Lets sync. Run this on your Source Node:

drbdadm -- --overwrite-data-of-peer primary resource

And watch it sync:

cat /proc/drbd

Heartbeat Integration

Once Heartbeat is setup, you can have an /etc/ha.d/haresources file like this:

node1 \
        drbddisk \    
        Filesystem::/dev/drbd0::/data::ext3 \
        IPaddr::192.168.42.100 \
        nfs