Appear in the Proceedings of the Usenix 1997 Technical Conference,
Anaheim, Jan. 1997.
Observing the Effects of Multi-Zone Disks
Rodney Van Meter
Information Sciences Institute
University of Southern California
Marina del Rey, CA 90292
[email protected]
(310) 822-1511
Abstract:
Current generations of hard disk drives use a technique known as
zoned constant angular velocity (ZCAV), taking advantage of the
geometry to increase total disk capacity by varying the number of disk
sectors per track with the distance from the spindle. A side effect of
this is that the transfer rate also varies with sector address. We
analytically estimated and measured this effect on file system
performance on a BSD Fast File System, showing a drop of roughly 25%
in peak transfer rate depending on head position. We also show that,
while ZCAV effects cannot be ignored, a simple linear model adequately
estimates the performance from the few parameters normally available
in disk drive spec sheets.
Paper
Sources
This work made use of several publicly available programs, which I
modified.
Bonnie
Written by Tim Bray. This tar file contains
what you need.
Scsiinfo
Written by John DiMarco.
- my modified version (tar file)
(more information on zone drives, plus translates logical to physical
addresses) (includes the below shar file, too)
- DiMarco's version 4.2beta2 (shar file)
- newer version at author's home page?
Fsblks
Written by Keith Smith.
Data
My data and Perl scripts for massaging it will be posted here soon.
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Rodney D. Van Meter III
Wed May 8 13:15:04 PDT 1996