Setup shared storage with DRBD

• Dedicated link for sync
• Same partition layout on all nodes
• Use LVM so that the volume can grow easily

   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1               1        8322     4194256+   5  Extended
/dev/sdb5               1        2033     1024569   8e  Linux LVM

pvcreate -M2 /dev/sdb5
vgcreate vg01 /dev/sdb5
lvcreate -l 100%FREE --name lv_vz vg01

We will use DRBD to mirror the lv_vz logical volume between all nodes.

Setup /etc/drbd.d/global_common.conf.

Note these:

• fence-peer
• after-resync-target
• fencing resource-only;
• rate 20M;

global_common.conf

global {
        usage-count no;
        # minor-count dialog-refresh disable-ip-verification
}

common {
        protocol C;

        handlers {
                pri-on-incon-degr "/usr/lib/drbd/notify-pri-on-incon-degr.sh; /usr/lib/drbd/notify-emergency-reboot.sh; echo b > /proc/sysrq-trigger ; reboot -f";
                pri-lost-after-sb "/usr/lib/drbd/notify-pri-lost-after-sb.sh; /usr/lib/drbd/notify-emergency-reboot.sh; echo b > /proc/sysrq-trigger ; reboot -f";
                local-io-error "/usr/lib/drbd/notify-io-error.sh; /usr/lib/drbd/notify-emergency-shutdown.sh; echo o > /proc/sysrq-trigger ; halt -f";

                fence-peer "/usr/lib/drbd/crm-fence-peer.sh";
                after-resync-target "/usr/lib/drbd/crm-unfence-peer.sh";

                # split-brain "/usr/lib/drbd/notify-split-brain.sh root";
                # out-of-sync "/usr/lib/drbd/notify-out-of-sync.sh root";
                # before-resync-target "/usr/lib/drbd/snapshot-resync-target-lvm.sh -p 15 -- -c 16k";
                # after-resync-target /usr/lib/drbd/unsnapshot-resync-target-lvm.sh;
        }

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                # wfc-timeout degr-wfc-timeout outdated-wfc-timeout wait-after-sb;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

        disk {
                # on-io-error fencing use-bmbv no-disk-barrier no-disk-flushes
                # no-disk-drain no-md-flushes max-bio-bvecs
                fencing resource-only;
        }

        net {
                # snd‐buf-size rcvbuf-size timeout connect-int ping-int ping-timeout max-buffers
                # max-epoch-size ko-count allow-two-primaries cram-hmac-alg shared-secret
                # after-sb-0pri after-sb-1pri after-sb-2pri data-integrity-alg no-tcp-cork
        }

        syncer {
                # rate after al-extents use-rle cpu-mask verify-alg csums-alg
                 rate 20M;
        }
}

Setup /etc/drbd.d/r0.res:

r0.res

resource r0 {
  device    /dev/drbd0;
  disk      /dev/mapper/vg01-lv_vz;
  meta-disk internal;
  on node1 {
    address   10.0.0.101:7789;
  }
  on node2 {
    address   10.0.0.102:7789;
  }
}

Restart drbd to take effect:

invoke-rc.d drbd restart

Init the disk:

drbdadm create-md r0
drbdadm attach r0
drbdadm syncer r0
drbdadm connect r0

At the primary node, assign the primary as the sync source and start sync:

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

Wait for sync complete:

 
node1:~# cat /proc/drbd

version: 8.3.7 (api:88/proto:86-91)
srcversion: EE47D8BF18AC166BE219757
 0: cs:Connected ro:Primary/Secondary ds:UpToDate/UpToDate C r----
    ns:1420 nr:0 dw:856 dr:21497 al:14 bm:10 lo:0 pe:0 ua:0 ap:0 ep:1 wo:b oos:0

Then format the DRBD block device as usual:

mkfs.ext3 /dev/drbd0

Let Pacemaker control the start/stop.

update-rc.d -f drbd remove