The Design and Implementation of a Log-structured file system: 303 (The Springer International Series in Engineering and Computer Science) - Hardcover

Rosenblum, Mendel

Hardcover

ISBN 10: 0792395417 ISBN 13: 9780792395416

Verlag: Springer, 1994

Inhaltsangabe

Computersystemsresearch is heavilyinfluencedby changesincomputertechnol­ ogy. As technology changes alterthe characteristics ofthe underlying hardware com­ ponents of the system, the algorithms used to manage the system need to be re­ examinedand newtechniques need to bedeveloped. Technological influencesare par­ ticularly evident in the design of storage management systems such as disk storage managers and file systems. The influences have been so pronounced that techniques developed as recently as ten years ago are being made obsolete. The basic problem for disk storage managers is the unbalanced scaling of hard­ warecomponenttechnologies. Disk storage managerdesign depends on the technolo­ gy for processors, main memory, and magnetic disks. During the 1980s, processors and main memories benefited from the rapid improvements in semiconductortechnol­ ogy and improved by several orders ofmagnitude in performance and capacity. This improvement has not been matched by disk technology, which is bounded by the me­ chanics ofrotating magnetic media. Magnetic disks ofthe 1980s have improved by a factor of 10in capacity butonly a factor of2 in performance. This unbalanced scaling ofthe hardware components challenges the disk storage manager to compensate for the slower disks and allow performance to scale with the processor and main memory technology. Unless the performance of file systems can be improved over that of the disks, I/O-bound applications will be unable to use the rapid improvements in processor speeds to improve performance for computer users. Disk storage managers must break this bottleneck and decouple application perfor­ mance from the disk.

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Reseña del editor

The Design and Implementation of a Log-Structured File System presents a new technique for disk storage management. A log-structured file system writes all modifications to disk sequentially in a log-like structure, thereby speeding up both file writing and crash recovery. The log is the only structure on disk; it contains indexing information so that files can be read back from the log efficiently. In order to maintain large free areas on disk for fast writing, the log is divided into segments and a segment cleaner to compress the live information from heavily fragmented segments. This book presents a series of simulations that demonstrate the efficiency of a simple cleaning policy based on cost and benefit. The author has implemented a prototype log-structured file system called Sprite LFS; it outperforms current Unix file systems by an order of magnitude for small-file writes while matching or exceeding Unix performance for reads and large writes. Even when the overhead for cleaning is included, Sprite LFS can use 70% of the disk bandwidth for writing, whereas Unix file systems typically can use only 5--10%.
The Design and Implementation of a Log-Structured File System demonstrates how a log-structured file system can be used more efficiently than existing file systems. This new system is well suited to the technology facing the disk storage manager.

Details zur Ausgabe

• Verlag: Springer
• Erscheinungsdatum: 1994
• Sprache: Englisch
• ISBN 10: 0792395417
• ISBN 13: 9780792395416
• Einband: Tapa dura
• Anzahl der Seiten: 148
• Kontakt zum Hersteller: ROXIO; https://www.also.com/ec/cms5/en_6000/6000/index.jsp; ; Friedrich-Karl-Str. 9; Hamburg; 22391; Deutschland