|
FAST 2002 Abstract
Track-aligned Extents:
Matching Access Patterns to Disk Drive Characteristics
Jiri Schindler, John Linwood Griffin, Christopher R. Lumb, Gregory R. Ganger
Carnegie Mellon University
Abstract
Track-aligned extents (traxtents) utilize disk-specific
knowledge to match access patterns to the strengths of
modern disks. By allocating and accessing related data
on disk track boundaries, a system can avoid most rotational
latency and track crossing overheads. Avoiding
these overheads can increase disk access efficiency by up
to 50% for mid-sized requests (100Ð500 KB). This paper
describes traxtents, algorithms for detecting track boundaries,
and some uses of traxtents in file systems and video
servers. For large-file workloads, a version of FreeBSD's
FFS implementation that exploits traxtents reduces application
run times by up to 20% compared to the original
version. A video server using traxtent-based requests can
support 56% more concurrent streams at the same startup
latency and buffer space. For LFS, 44% lower overall
write cost for track-sized segments can be achieved.
- View the full text of this paper in
HTML,
PDF, and
PostScript. Until January 2003, you will need your USENIX membership identification in order to access the full papers.
The Proceedings are published as a collective work, © 2002 by the USENIX Association. All Rights Reserved. Rights to individual papers remain with the author or the author's employer. Permission is granted for the noncommercial reproduction of the complete work for educational or research purposes. USENIX acknowledges all trademarks within this paper.
- If you need the latest Adobe Acrobat Reader, you can download it from Adobe's site.
- To become a USENIX Member, please see our Membership Information.
|
Need help? Use our Contacts page.
