Hi,
if you want to share this vxfs file system in the cluster you may use vgchange -a s <vgroup>. This may leave sharable the file system for both nodes (normaly is mounted as vgchange -a e <vgroup> avoiding writes from the standby node). Please, try to consult vgchange manual on your HP-UX and see information related to this mode.
This mode is for a parallel Oracle Server?
Hope this would help you.
Best regards,