You can see that there is a file system shared between the two systems, and the same Integration node is able to run on either system.
There are two technology options for enabling HA failover of an Integration Node as follows:
1. Use the built-in multi-instance feature of IBM Integration Bus
Requires a highly available network-attached filesystem, such as IBM GPFS or a highly available NFSv4 file server.
See this TechNote for details of filesystem requirements.
2. Use a HA Clustering technology, such as IBM PowerHA (formerly HACMP), Microsoft Cluster Server or Veritas Cluster Server
These technologies allows use of fibre-attached SAN or shared-SCSI storage.
For more details on choosing an appropriate HA Failover technology, see Using WebSphere MQ with high availability configurations in the MQ information center.