This has stumped me  a few times because I keep forgetting that Centos 5.5 comes with a default iptables configuration that ends up blocking DRBD traffic, I tried all the normal things and couldn't understand why I couldn't make my normal DRBD config work.  So if you have WFConnection problems and have tried the normal "mailing list" fixes, check your firewall status first!


Both Nodes Say the Following:

version: 8.3.8 (api:88/proto:86-94)
GIT-hash: d78846e52224fd00562f7c225bcc25b2d422321d build by mockbuild@builder10.centos.org, 2010-06-04 08:04:16
 0: cs:WFConnection ro:Secondary/Unknown ds:Diskless/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:0

drbdadm primary r0

0: State change failed: (-2) Need access to UpToDate data
Command 'drbdsetup 0 primary' terminated with exit code 1

drbdadm invalidate-remote r0

0: State change failed: (-4) Can not resync without local disk
Command 'drbdsetup 0 invalidate-remote' terminated with exit code 16

Here's what I should have done:

drbdadm create-md r0

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

On both nodes:

drbdadm attach r0
drbdadm connect r0

On Primary:

drbdsetup /dev/drbd0 primary -o