This topic provides a brief overview of IBM® TotalStorage® SAN File System.
IBM TotalStorage SAN File System is a storage area network (SAN)-based, scalable, and highly-available file system and storage management solution for file aggregation and concurrent data sharing in an open, multi-platform environment. It uses SAN technology, which allows an enterprise to connect a large number of heterogeneous computers and share a large number of heterogeneous storage devices over a high-performance network.
With SAN File System, heterogeneous clients can access shared data directly from large, high-performance, high-function storage systems, such as IBM TotalStorage Enterprise Storage Server® (ESS) and IBM TotalStorage SAN Volume Controller. SAN File System is built on a Fibre Channel network and is designed to provide superior I/O performance for data sharing among heterogeneous computers. It also provides growth capability and simplified storage management.
SAN File System differs from conventional distributed file systems in that it uses a data-access model that separates file metadata (information about the files, such as owner, permissions, and the physical file location) from actual file data (contents of the files). The metadata is provided to clients by the metadata servers. Clients communicate with the metadata servers only to get the information they need to locate and access the files. Once they have this information, SAN File System clients can access data directly from the storage devices through the clients' own direct connection to the SAN. Direct data access eliminates server bottlenecks and provides the performance necessary for data-intensive applications.
SAN File System presents a single, global namespace in which clients can create and share data using uniform file names from any client or application. Data consistency and integrity are maintained through SAN File System's management of distributed locks and the use of leases. SAN File System provides locks that enable file sharing among SAN File System clients, and when necessary, provides locks that allow clients to have exclusive access to files. A lease determines the maximum period of time that a metadata server guarantees the locks that it grants to clients. A client must contact the metadata server before the lease period ends to retain its locks.
SAN File System also provides automatic file placement and management through the use of policies and rules. Based on the rules specified in centrally-defined and managed policies, SAN File System automatically stores, moves, and deletes data in storage pools that are specifically created to provide the capabilities and performance appropriate for how the data is accessed and used.
Parent topic: Overview of SAN File System