Managing Serviceguard Extension for SAP on Linux (IA64 Integrity and x86_64), February 2008

Planning a File System Layout for SAP in a Serviceguard/LX Cluster Environment
About Impacted File Systems
Chapter 2 51
SHARED EXCLUSIVE This type of storage mounts, relocates the
storage volume together with the relocation of the application and the
Serviceguard package from one cluster node to another cluster node. The
file system is exclusively mounted on the node the application is running
on. The file system is not mounted by any of the other cluster nodes or
accessed by these. Compared to the SHARED NFS category this solution
will provide the highest I/O performance.
However, there is the disadvantage and the risk of a failure during the
relocation of the file systems to another cluster node. Any failure in the
sequence of stopping the application, unmounting the file systems,
deactivating the access to the storage devices on the first cluster node;
activating the access to the storage devices on the second node, mounting
the file systems will cause the startup of the application to fail.
NOTE In prior SGeSAP/LX documentation this category was called “Instance
specific.”