Trying To Save Even More Power With Fedora On The NC10
It is becoming and obsession with me to save power on my NC10. Here are some more tweaks
I noticed that Fedora was causing disk access regularly and it was not obvious why. As it turns out, it was partly due to the super cleaver ext4 file system. The super cleaver thing is journalling, IE it does not write everything to the hard drive straight away but it does maintain a record of changes that are about to happen so that data does not get damaged in the even of a crash. This approach can also have a big impact on performance by improving the way in which data can be cached in memory rather than written to disk.
All this is great, except that the journalling system keeps writing the journal to the hard drive every 5 seconds. This stops the hard drive from going into sleep mode and so waists a lot of power and could in theory have an impact on the lifespan of the drive.
However, there is a solution. In /etc/fstab one can set the time between flushes of the journal via a commit= mount option. I have set mine to 5 minutes - to match the setting of the dirty page flush on the disk cache. Here is my new fstab:
# # /etc/fstab # Created by anaconda on Fri Jun 26 00:10:24 2009 # # Accessible filesystems, by reference, are maintained under '/dev/disk' # See man pages fstab(5), findfs(8), mount(8) and/or vol_id(8) for more info # UUID=a4788b77-43e7-4609-a324-93a9f6102820 /boot ext3 noatime,commit=300 1 2 /dev/mapper/vg_ajtnetbook-lv_root / ext4 noatime,commit=300 1 1 /dev/mapper/vg_ajtnetbook-lv_swap swap swap defaults 0 0 tmpfs /dev/shm tmpfs defaults 0 0 devpts /dev/pts devpts defaults 0 0 sysfs /sys sysfs defaults 0 0 proc /proc proc defaults 0 0 none /sys/bus/usb/drivers usbfs devgid=501,devmode=664 0 0
Another Trick
I do a lot of blogging. Writing up in abi word is better than Firefox before every time Firefox does a spell check it reads from the hard drive and so wakes it up :(
