我们正在通过安装在运行kernel-3.10.0-862.el7的Centos-7.4中的DRBD构建主动-被动集群。使用drbadm创建群集时，无法创建卷并给出以下错误。你能帮我吗？
open(/dev/vdb) failed: Invalid argument
could not open with O_DIRECT, retrying without
'/dev/vdb' is not a block device!
open(/dev/vdb) failed: Invalid argument
could not open with O_DIRECT, retrying without
'/dev/vdb' is not a block device!
Command 'drbdmeta 0 v08 /dev/vdb internal create-md' terminated with exit code 20