Everytime I've seen this error "/dev/drbd0: State change failed: (-2) Need access to UpToDate data" it is because DRBD has no disk:
cat /proc/drbd
version: 8.3.13 (api:88/proto:86-96)
GIT-hash: 83ca112086600faacab2f157bc5a9324f7bd7f77 build by root@sighted, 2012-10-09 12:47:51
0: cs:Connected ro:Secondary/Secondary ds:Diskless/Inconsistent A r-----
ns:0 nr:0 dw:0 dr:0 al........