A reimplementation of the UNIX file system is described. The reimplementation provides substantially higher throughput rates by using more flexible allocation policies that allow better locality of reference and can be adapted to a wide range of peripheral and processor characteristics. The new file system clusters data that is sequentially accessed and provides two block sizes to allow fast access to large files while not wasting large amounts of space for small files. File access rates of up to ten times faster than the traditional UNIX file system are experienced. Long needed enhancements to the programmers’ interface are discussed. These include a mechanism to place advisory locks on files, extensions of the name space across file systems, the ability to use long file names, and provisions for administrative control of resource usage.

Over the last few years, there have been several efforts to use logging to improve performance, reliability, and recovery times of file systems. The two major techniques are metadata logging, where the log records metadata changes and is a supplement to the on-disk file system, and logstructured file systems, whose log is their only ondisk representation. When the file system is mainly or wholly accessed through the Network File System (NFS) protocol, it adds new considerations to the suitability of the logging technique. NFS requires that all operations be updated to stable storage before returning. As a result, file system implementations that were effective for local access may perform poorly on an NFS server. This paper analyzes the issues regarding the use of logging on an NFS server, and describes an implementation of a BSD Fast File System (FFS) with metadata logging that performs effectively for a dedicated NFS server. 1.

In this paper we introduce DualFS, a new high performance journaling file system that puts data and meta-data on different devices (usually, two partitions on the same disk or on different disks), and manages them in very different ways. Unlike other journaling file systems, DualFS has only one copy of every meta-data block. This copy is in the metadata device, a log which is used by DualFS both to read and to write meta-data blocks. By avoiding a time-expensive extra copy of meta-data blocks, DualFS can achieve a good performance as compared to other journaling file systems. Indeed, we have implemented a DualFS prototype, which has been evaluated with microbenchmarks and macrobenchmarks, and we have found that DualFS greatly reduces the total I/O time taken by the file system in most cases (up to 97%), whereas it slightly increases the total I/O time only in a few and limited cases.

A reimplementation of the UNIX file system is described. The reimplementation provides substantially higher throughput rates by using more flexible allocation policies that allow better locality of reference and can be adapted to a wide range of peripheral and processor characteristics. The new file system clusters data that is sequentially accessed and provides two block sizes to allow fast access to large files while not wasting large amounts of space for small files. File access rates of up to ten times faster than the traditional UNIX file system are experienced. Long needed enhancements to the programmers ' interface are discussed. These include a mechanism to place advisory locks on files, extensions of the name space across file systems, the ability to use long file names, and provisions for administrative control of resource usage. Revised February 18, 1984 CR Categories and Subject Descriptors: D.4.3 [Operating Systems]: File Systems Management - file organization, directory s...

: In most modern local area network environments, NFS is used to provide remote file storage on a particular server machine. A consequence of this distributed architecture is that the failure of the server results in paralysis or a loss of work for users. This paper presents the design of a low-cost fault tolerant NFS server which can be installed on most Unix networking environments. FT-NFS runs as a user process and does not necessitate any underlying specific operating system functionality. The originality of our approach relies on the use of a stable cache which provides data availability and resiliency to a single failure. The main benefits of the stable cache are first to allow disk write operations to be safely performed in the background and second to permit the gathering of small files in large containers. The latter technique permits disk I/Os to be improved by reducing their number and increasing their length. Under the nhfsstone benchmark, FT-NFS outperforms the in-kernel S...