By Topic

Analysis of reorganization overhead in log-structured file systems

Sign In

Cookies must be enabled to login.After enabling cookies , please use refresh or reload or ctrl+f5 on the browser for the login options.

Formats Non-Member Member
$31 $13
Learn how you can qualify for the best price for this item!
Become an IEEE Member or Subscribe to
IEEE Xplore for exclusive pricing!
close button

puzzle piece

IEEE membership options for an individual and IEEE Xplore subscriptions for an organization offer the most affordable access to essential journal articles, conference papers, standards, eBooks, and eLearning courses.

Learn more about:

IEEE membership

IEEE Xplore subscriptions

2 Author(s)
Robinson, J.T. ; Div. of Res., IBM Thomas J. Watson Res. Center, Yorktown Heights, NY, USA ; Franaszek, Peter A.

In a log-structured file system (LFS), in general each block written to disk causes another disk block to become invalid data, resulting in one block of free space. Over time free disk space becomes highly fragmented, and a high level of dynamic reorganization may be required to coalesce free blocks into physically contiguous areas that subsequently can be used for logs. By consuming available disk bandwidth, this reorganization can degrade system performance. In a segmented disk LFS organization, the copy-and-compact reorganization method reads entire segments and then writes back all valid blocks. Other methods, suggested by earlier work on reduction of storage fragmentation for non-LFS disks, may access far fewer blocks (at the cost of increased CPU time). An analytic model is used to evaluate the effects on available disk bandwidth of dynamic reorganization, as a function of the read/write ratio, storage utilization, and degree of data movement required by dynamic reorganization for steady-state operation. It is shown that decreasing reorganization overhead can have dramatic effects on available disk bandwidth

Published in:

Data Engineering, 1994. Proceedings.10th International Conference

Date of Conference:

14-18 Feb 1994