GFS2
also: Global File System 2, clustered file system
GFS2 (Global File System 2) is a shared-disk cluster file system that allows multiple nodes to access and modify the same file system simultaneously over a network, with built-in locking and consistency mechanisms.
GFS2 is a symmetric cluster file system developed by Red Hat that enables several computers (nodes) to mount and use the same file system concurrently. Unlike traditional file systems designed for single-node access, GFS2 coordinates access across multiple nodes using a distributed locking mechanism to prevent data corruption.
GFS2 requires shared storage (typically a SAN or iSCSI target) and cluster management software like Pacemaker to detect node failures and manage cluster membership. It is commonly used in high-availability and load-balancing clusters where multiple servers need simultaneous access to the same data.
Example: A two-node database cluster might mount /dev/sda1 as GFS2 on both servers; when node A writes to a file, GFS2's lock manager ensures node B sees the updated data, and if node A fails, node B continues accessing the file system without corruption.