Clustered file systems (CFS) are file systems that run on multiple storage servers and can be accessed and managed as a single system.
A CFS pulls together and shares storage capacity that is available, but not always used, on storage networks. This increases storage utilization rates, and can result in better performance. Most clustered file systems incorporate a volume manager, which allows an administrator to allocate capacity.
A traditional file system manages storage retrieval between an operating system (OS) and storage system, but this can be made more complex when servers are organized into one cluster. A CFS can organize the storage and access data across all clusters.
If the cluster is just meant to provide redundancy when one node fails, each server can operate autonomously and a clustered file system is not required. However, if the clusters work collaboratively and handle more demanding tasks, a CFS may be necessary. The CFS allows users to access the same files and data concurrently.
The clustered file system also controls the node's access to the shared storage, which prevents multiple nodes from creating overlapping writes.