For a cluster of servers that span multiple systems in a sysplex and will have stateful session beans with an activation policy of Transaction deployed in them, the passivation directory should reside on an HFS (hierarchical file system) that is shared across the multiple systems in the sysplex on which the clustered servers will be running.
/WebSphere/V6R0M0/AppServer/passivation/cluster1
For optimal performance, you should create a passivation directory for each cluster. Also, the default passivation directory should not be used for clusters; it should be used for non-clustered servers and servers that do not have stateful session beans with an activation policy of Transaction.
For information about defining a shared HFS, see z/OS UNIX System Services Planning.
For information on specifying the passivation directory with the WebSphere administrative console, see EJB container settings.