In a SAN environment, a disk unit can be accessed from multiple servers.
GDS provides a single system image environment, in which a cluster system with multiple servers (also referred to as nodes) appears as one system to the users or application.
This single system image environment can be utilized as explained below.
Application programs sharing the same disk can lookup disks and volumes using the same name from all nodes.
Application programs can access the disk simultaneously from all nodes. For details, see "Note."
Application programs can perform operations from all nodes, such as changing the configuration on objects (such as disks and volumes). Changes are reflected on all nodes.
Figure 1.20 Single System Image Environment
Note
Access Exclusion Control
When the same block is accessed simultaneously, data consistency is maintained by access exclusion control performed by the application that runs on multiple nodes simultaneously.
