Procedure 13.1. Manually Configure DRBD

1. Log in as user root.

2. Change DRBD's configuration files:

   1. Open the file /etc/drbd.conf and insert the following lines, if not available:

      include "drbd.d/global_common.conf";
      include "drbd.d/*.res";

      Beginning with DRBD 8.3 the configuration file is split into separate files, located under the directory /etc/drbd.d.

   2. Open the file /etc/drbd.d/global_common.conf. It contains already some pre-definied values. Go to the startup section and insert these lines:

      startup {
          # wfc-timeout degr-wfc-timeout outdated-wfc-timeout
          # wait-after-sb;
          wfc-timeout 1;
          degr-wfc-timeout 1;
      }

      These options are used to reduce the timeouts when booting, see http://www.drbd.org/users-guide-emb/re-drbdconf.html for more details.

   3. Create the file /etc/drbd.d/r0.res, change the lines according to your situation, and save it:

      resource r0 { 
        device /dev/drbd_r0 minor 0; 
        disk /dev/sda1; 
        meta-disk internal; 
        on jupiter { 
          address  192.168.1.10:7780; 
        }
        on venus { 
          address 192.168.1.11:7780; 
        }
        syncer {
          rate  7M; 
        }
      }

      	Name of the resource. It is recommended to use resource names like r0, r1, etc.
      	The device name for DRBD and its minor number. It is recommended to start with /dev/drbd and append your resource name (r0 in this case).
      	The device that is replicated between nodes. Note, in this example the devices are the same on both nodes. If you need different devices, move the disk parameter into the on section.
      	The meta-disk parameter usually contains the value internal, but it is possible to specify an explict device to hold the meta data. See http://www.drbd.org/users-guide-emb/ch-internals.html#s-metadata for more information.
      	The on section contains the hostname of the node
      	The IP address and port number of the respective node. Each resource needs an individual port, usually starting with 7780.
      	The syncronization rate. Set it to one third of your bandwith. It only limits the resyncronization, not the mirroring.

3. Check the syntax of your configuration file(s). If the following command returns an error, verify your files:

   drbdadm dump all

4. Copy the DRBD configuration files to the other node:

   scp /etc/drbd.conf venus:/etc/
   scp /etc/drbd.d/*  venus:/etc/drbd.d/

5. Initialize the meta data on both systems by entering the following on each node.

   drbdadm -- --ignore-sanity-checks create-md r0
   rcdrbd start

   If your disk contains already a filesystem that you do not need anymore, destroy the filesystem structure with the following command and repeat this step:

   dd if=/dev/zero of=/dev/sdb1 count=10000

6. Watch the DRBD status by entering the following on each node:

   rcdrbd status

   You should get something like this:

   drbd driver loaded OK; device status:
   version: 8.3.7 (api:88/proto:86-91)
   GIT-hash: ea9e28dbff98e331a62bcbcc63a6135808fe2917 build by phil@fat-tyre, 2010-01-13 17:17:27
   m:res  cs         ro                   ds                         p  mounted  fstype
   0:r0   Connected  Secondary/Secondary  Inconsistent/Inconsistent  C

7. Start the resync process on your intented primary node (jupiter in this case):

   drbdadm -- --overwrite-data-of-peer primary r0

8. Check the status again with rcdrbd status and you get:

   ...
   m:res  cs         ro                 ds                 p  mounted  fstype
   0:r0   Connected  Primary/Secondary  UpToDate/UpToDate  C

   The status in the ds row (disk status) must be UpToDate on both nodes.

9. Set jupiter as primary node:

   drbdadm primary r0

10. Create your filesystem on top of your DRBD device, for example:

    mkfs.ext3 /dev/drbd_r0

11. Mount the file system and use it:

    mount /dev/drbd_r0 /mnt/

1. Test the DRBD service on jupiter.

   1. Open a terminal console, then log in as root.

   2. Create a mount point on jupiter, such as /srv/r0mount:

      mkdir -p /srv/r0mount

   3. Mount the drbd device:

      mount -o rw /dev/drbd0 /srv/r0mount

   4. Create a file from the primary node:

      touch /srv/r0mount/from_node1

2. Test the DRBD service on venus.

   1. Open a terminal console, then log in as root.

   2. Unmount the disk on jupiter:

      umount /srv/r0mount

   3. Downgrade the DRBD service on jupiter by typing the following command on jupiter:

      drbdadm secondary r0

   4. On venus, promote the DRBD service to primary:

      drbdadm primary r0

   5. On venus, check to see if venus is primary:

      rcdrbd status

   6. On venus, create a mount point such as /srv/r0mount:

      mkdir /srv/r0mount

   7. On venus, mount the DRBD device:

      mount -o rw /dev/drbd0 /srv/r0mount

   8. Verify that the file you created on jupiter is viewable.

      ls /srv/r0mount

      The /srv/r0mount/from_node1 file should be listed.

3. If the service is working on both nodes, the DRBD setup is complete.

4. Set up jupiter as the primary again.

   1. Dismount the disk on venus by typing the following command on venus:

      umount /srv/r0mount

   2. Downgrade the DRBD service on venus by typing the following command on venus:

      drbdadm secondary r0

   3. On jupiter, promote the DRBD service to primary:

      drbdadm primary r0

   4. On jupiter, check to see if jupiter is primary:

      rcdrbd status

5. To get the service to automatically start and fail over if the server has a problem, you can set up DRBD as a high availability service with OpenAIS. For information about installing and configuring OpenAIS for SUSE Linux Enterprise 11 see Part II, “Configuration and Administration”.