参考
FAQ
"drbdadm create-md r0: exited with code 40"
这个错误比较常见：
Device size would be truncated, which would corrupt data and result in 'access beyond end of device' errors. You need to either * use external meta data (recommended) * shrink that filesystem first * zero out the device (destroy the filesystem) Operation refused. Command 'drbdmeta 0 v08 /dev/xvdb internal create-md' terminated with exit code 40 drbdadm create-md r0: exited with code 40
可以这样解决：
dd if=/dev/zero bs=1M count=1 of=/dev/sdXYZ; sync drbdadm create-md $r drbdadm -- -o primary $r mkfs /dev/drbdY
