Jonathan Corbet
Various fixes have been gathered on the Ubuntu wiki page, but the basic
idea is to change the power savings setting for the hard disk using hdparm
-B 254 /dev/hda (or /dev/sda). The 254 value sets the least aggressive
power savings mode; some users are reporting that 255 will disable power
management completely, while others say it has no effect.
The biggest change distributions can make to help alleviate this problem is
to reduce the number of writes, especially nearly useless writes, to the
disk. One of the culprits reported for Ubuntu is the acpid power management
daemon writing battery status to a logfile every 15 seconds, which seems
like a good way to ensure the battery life reduces more quickly than it
should. Some logging could be deferred or disabled when running from
battery.
Using the relatime option when mounting filesystems is another, fairly
simple, change that could be made to significantly reduce disk writes that
are likely to be pointless. Fedora 8 enables that option by default for all
systems, battery powered or not, for the disk performance increase that it
gives. People running older kernels, before 2.6.20 added the relatime
option, may want to consider disabling atime updates altogether using the
noatime mount option.
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