7.2.3. Initialize and Load DRBD

With the configuration in place, we can now perform the DRBD initialization

[root@pcmk-1 ~]# drbdadm create-md wwwdata
md_offset 12578816
al_offset 12546048
bm_offset 12541952

Found some data 
 ==> This might destroy existing data! <==

Do you want to proceed?
[need to type 'yes' to confirm] yes

Writing meta data...
initializing activity log
NOT initialized bitmap
New drbd meta data block successfully created.
success

Now load the DRBD kernel module and confirm that everything is sane

[root@pcmk-1 ~]# modprobe drbd
[root@pcmk-1 ~]# drbdadm up wwwdata
[root@pcmk-1 ~]# cat /proc/drbd
version: 8.3.6 (api:88/proto:86-90)
GIT-hash: f3606c47cc6fcf6b3f086e425cb34af8b7a81bbf build by root@pcmk-1, 2009-12-08 11:22:57

 1: cs:WFConnection ro:Secondary/Unknown ds:Inconsistent/DUnknown 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:12248
[root@pcmk-1 ~]# 

Repeat on the second node
drbdadm --force create-md wwwdata 
modprobe drbd
drbdadm up wwwdata
cat /proc/drbd
[root@pcmk-2 ~]# drbdadm --force create-md wwwdata
Writing meta data...
initializing activity log
NOT initialized bitmap
New drbd meta data block successfully created.
success
[root@pcmk-2 ~]# modprobe drbd
WARNING: Deprecated config file /etc/modprobe.conf, all config files belong into /etc/modprobe.d/.
[root@pcmk-2 ~]# drbdadm up wwwdata
[root@pcmk-2 ~]# cat /proc/drbd
version: 8.3.6 (api:88/proto:86-90)
GIT-hash: f3606c47cc6fcf6b3f086e425cb34af8b7a81bbf build by root@pcmk-1, 2009-12-08 11:22:57

 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:12248

Now we need to tell DRBD which set of data to use. Since both sides contain garbage, we can run the following on pcmk-1:

[root@pcmk-1 ~]# drbdadm -- --overwrite-data-of-peer primary wwwdata
[root@pcmk-1 ~]# cat /proc/drbd
version: 8.3.6 (api:88/proto:86-90)
GIT-hash: f3606c47cc6fcf6b3f086e425cb34af8b7a81bbf build by root@pcmk-1, 2009-12-08 11:22:57
 1: cs:SyncSource ro:Primary/Secondary ds:UpToDate/Inconsistent C r----
    ns:2184 nr:0 dw:0 dr:2472 al:0 bm:0 lo:0 pe:0 ua:0 ap:0 ep:1 wo:b oos:10064
        [=====>..............] sync'ed: 33.4% (10064/12248)K
        finish: 0:00:37 speed: 240 (240) K/sec
[root@pcmk-1 ~]# cat /proc/drbd
version: 8.3.6 (api:88/proto:86-90)
GIT-hash: f3606c47cc6fcf6b3f086e425cb34af8b7a81bbf build by root@pcmk-1, 2009-12-08 11:22:57
 1: cs:Connected ro:Primary/Secondary ds:UpToDate/UpToDate C r----
    ns:12248 nr:0 dw:0 dr:12536 al:0 bm:1 lo:0 pe:0 ua:0 ap:0 ep:1 wo:b oos:0

pcmk-1 is now in the Primary state which allows it to be written to. Which means its a good point at which to create a filesystem and populate it with some data to serve up via our WebSite resource.