Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
You missed a step. The resource must be primary before you can create the filesystem. Promote it on one of your nodes and try mkfs again... # drbdadm primary r0 # mkfs .... Only do this on one node, as the file system will be replicated by DRBD to the other (secondary) node.