Unless you are employing a global, or cluster, filesystem that is the expected behavior.   Each node believes it owns that disk exclusively.  It does not periodically coordinate or re-read the disk contents.  This is what is known as a "Double Mount".  It will cause corruption in the long term, 100% certainty.  As one node will select a block to write to, and the other node could use that same one.  Or if you reboot a node it will flush out the state of the disk as it knows it.   So you need to address this IMMEDIATELY.   On the 'inactive' node remove power cord, do NOT shutdown the node.  Otherwise it will flush out cache.  (or pull network cables then shutdown)   On the active node, unmount the partitions and run fsck on them.  
Hello,I have 2 hosts (PowerEdge R710) running Oracle Enterprise Linux 5.7, accessing a storage (PowerVault MD3200i) directly connected (no switches in between). Also I have installed and configured multipath. Everything seemed to be working fine, until I noticed that when I make a change to the storage from host-1 (for example:creating a file) this change cannot be seen by host-2 while accessing the same storage (same directory)! In fact the only way host-2 could see the change was after a reboot... Can anyone give me a hint of what I could be doing wrong?  :)Thanks in advance.
Concurrency on the Storage