sorry for the late reply.
> SLES (version 11SP3)
do you have any driving need to use that out-of-date version, rather than SP4?
> What i expect is when node A down, B can still use the disk. When node B down, node A can still use the disk.
> What step that i missing to achieve my expectation?
how did you set up the cluster regarding quorum and how to react to a no-quorum situation?