Red Hat Bugzilla – Bug 89718
Magicdev significantly slows down disk speed
Last modified: 2007-04-18 12:53:19 EDT
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Description of problem:
Enabling magicdev significantly slows down disk access. That is, leaving
magicdev running to poll for music cds or to auto-mount data CDS, has a major
impact on the performance of the harddrive.
I have a Dell Inspiron 8200 laptop. P4 2.2GHz with an IBM 5400 RPM 40 gig hd.
the hard drive is hda and a dvd/cdrw is hdb. Hdb is set to ide-scsi so the
burner can be used.
Leaving magicdev on, hdparm reports disk speeds of 14-18 meg/sec.
However, the disk feels significantly slower than that. Programs like mozilla
and openoffice take upwards of a minute to run. With magicdev shutoff, hdparm
consistantly reports a disk speed of 26 meg/sec. Moreover, application loading
This bug/feature of magicdev is not well documented, I've had this problem for
months before I accidentily stumbled upon someone else encountering the same
problem and recommending to kill magicdev. Before, I assumed the kernel was not
correctly dealing with my IDE controller, and i'd need to upgrade the kernel to
fix disk speed (which I was giong to get around to in the summer).
Version-Release number of selected component (if applicable):
RedHat 9.0, magicdev-1.1.4-4
Steps to Reproduce:
1. Enable MagicDev
Actual Results: Slow Disk Speed
Expected Results: Disk speed remains constant
I am experiencing the same problem on a Dell M50 with a Western Digital 40GB
IDE drive. I'm running redhat 7.2. When executing "hdparm -tT </dev/hdX>" with
magicdev running I get disk reads of 1-2MB's/sec. When I kill magicdev disk
reads go up to and are consistant at 22MB's/sec. Until a better solution is
found I am going to remove the magicdev package and enable automount for the
cdrom and floppy devices.
The interesting question here is really the exact model of the CD-ROM involved
(though that is less of a sensible question for the laptop). The basic problem
here is that the CD-ROM doesn't respond properly to magicdev's probe and that
screws up the bus for some period of time.
(Note that if you can possibly put your CD-ROM on a different IDE channel
than your hard drive, you'll be better off)
*** This bug has been marked as a duplicate of 73661 ***
The root-cause might be related to
but there is not enough data above to be sure.
Changed to 'CLOSED' state since 'RESOLVED' has been deprecated.