Overview of the SAN and Nasan File Systems

DataPlow, Inc. is committed to providing customers with quality, high-performance, storage area network (SAN) management software.  SANs are dedicated, high-speed networks that directly connect multiple computers to central pools of disk storage.  The SAN File System (SFS) and the Nasan file system are SAN-based, high-performance distributed file systems developed by DataPlow.  Both SAN file systems exploit the high-speed, scalable data transfers inherent to SANs and thus possess similar performance characteristics.  Though architecturally equivalent, the file systems are tuned for different environments and applications.

The SAN File System utilizes high-speed SAN connections for both read and write operations.  SFS relies on a fine-grained locking mechanism to maintain data consistency among clients.  This locking mechanism imposes latency overheads.  These overheads are negligible for file transfers greater than two hundred kilobytes yet large enough to make small file transfers less efficient.  Consequently, SFS is particularly well suited for medium to large file, read/write-intensive applications where bandwidth and scalability are critical.

In contrast, the Nasan file system utilizes high-speed SANs and central NAS servers.  The combination of these technologies facilitates extremely low-latency consistency management.  Low-latency consistency enables Nasan clients to efficiently transfer files of all sizes.  The Nasan file system is an ideal, general-purpose file sharing solution for read-intensive workloads.