Red Hat Enterprise Linux Resilient Storage add-on lets users access the same storage device over a network - using either shared storage or a clustered file system - through a pool of data, that's available to each server in a group. Each server in a cluster has direct access to a shared block device over a local storage area network (SAN). This add-on includes the Global File System 2 to support concurrent access, a cluster-wide locking mechanism to arbitrate storage access, a POSIX-compliant file system across 16 nodes, and Clustered Samba or Common Internet File System for Windows environments.