[ubuntu-za] Changing filesystems

[Josh Brodrick]

>
>
>
> Ted T'so finds ext4 to be OK for SSD if you use noatime, and also
> shows using ext4 without a journal:
> http://thunk.org/tytso/blog/2009/03/01/ssds-journaling-and-noatimerelatime/
>
> There are tips for moving your log files to tmpfsen:
> http://ubuntuforums.org/showthread.php?t=1178209
>
> Regards
> Morgan
>
>
Hi Morgan

Thanks for the links. I am already using noatime, as well as a tempfs in
ram. I also use elevator=noop scheduler.
Just two things with regard to those links you gave me:

firstly i think im missing something, but how do i actually go about
disabling journaling on my ext4?

Secondly there is quite a long list of fixes as suggested below:

Quote:
  SSD Optimization
Perform the following if you’re using an SSD. If you’re using a hard drive
you can skip this section.
Create Ramdisks to Store Frequently Written Areas

1. Edit your /etc/fstab file. Add the following lines.
tmpfs /var/log tmpfs defaults 0 0
tmpfs /tmp tmpfs defaults 0 0
tmpfs /var/tmp tmpfs defaults 0 0

Disable Access Time Attributes

1. Edit your /etc/fstab. Modify the root partitions settings. Add noatime
and nodiratime to defaults.
/dev/sda2 / ext4 defaults,noatime,nodiratime 0 0

Optimizing the Kernel

1. Add the following to your /etc/rc.local file.
# Economize the SSD
sysctl -w vm.swappiness=1 # Strongly discourage swapping
sysctl -w vm.vfs_cache_pressure=50 # Don't shrink the inode cache
aggressively

# As in the rc.last.ctrl of Linpus
echo ondemand > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor
echo ondemand > /sys/devices/system/cpu/cpu1/cpufreq/scaling_governor
cat /sys/devices/system/cpu/cpu0/cpufreq/ondemand/sampling_rate_max >
/sys/devices/system/cpu/cpu0/cpufreq/ondemand/sampling_rate

echo 1500 > /proc/sys/vm/dirty_writeback_centisecs
echo 20 > /proc/sys/vm/dirty_ratio
echo 10 > /proc/sys/vm/dirty_background_ratio

echo 1 > /sys/devices/system/cpu/sched_smt_power_savings
echo 10 > /sys/module/snd_hda_intel/parameters/power_save
echo 5 > /proc/sys/vm/laptop_mode

#Decrease power usage of USB while idle
[ -w /sys/bus/usb/devices/1-5/power/level ] && echo auto >
/sys/bus/usb/devices/1-5/power/level
[ -w /sys/bus/usb/devices/5-5/power/level ] && echo auto >
/sys/bus/usb/devices/5-5/power/level

/sbin/setpci -d 197b:2381 AE=47
/sbin/modprobe pciehp
/sbin/modprobe sdhci

Change the I/O Scheduler

1. Edit the /etc/grub.conf file. Add “elevator=noop” to the kernel line.
kernel /vmlinuz-2.6.27.5-117.fc10.i686 ro root=/dev/sda
Source: http://forums.fedoraforum.org/showthread.php?t=215109


Im not sure i completely understand all the mentioned suggestions,
especially the "dirty-writeback"s and also the usb power saving...
are these safe to use or implement?

Thanks again for all the help everyone!

Cheers
Josh



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