View source for Solid State Drive tweaks

[[Category:Ubuntu]]
[[Category:Ubuntu System]]
[[Category:201110]]
* https://wiki.ubuntu.com/MagicFab/SSDchecklist

==Prepare==

# check for ssd firmware updates
# Enable SATA AHCI mode in the BIOS (if available)

Note: in a dual boot configuration with Windows 7, Windows will not boot after changing AHCI. You will need to make some changes in Windows before proceeding.

==Format SSD==

'''Update: it is better to have journaling enabled for possible fault correction. Skip this section.'''

Format drive as ext4, journaling disabled.

MAKE SURE WE ARE TALKING ABOUT THE RIGHT DRIVE HERE

Physical drive: "sdb", partition "sdb1"

<syntaxhighlight lang=bash>	
sudo fdisk -l /dev/sdb | grep sectors
</syntaxhighlight>	

 255 heads, 63 sectors/track, 7297 cylinders

<syntaxhighlight lang=bash>	
sudo fdisk -H 255 -S 63 /dev/sdb
 "d" delete partition
 "n" new partition, primary, 1
 "w" to write partition table and exit
sudo mke2fs -t ext4 -O ^has_journal /dev/sdb1
</syntaxhighlight>

==Access time==

The "relatime" option writes the time-of-access to disk and causes unnecessary additional writes to disk. Mount volumes using the "noatime" option in stead of the "relatime" option.

<syntaxhighlight lang=bash>
sudo cp /etc/fstab ~/fstab-backup
sudo gedit /etc/fstab
</syntaxhighlight>

Notice the location of 'noatime,'. Do not change anything else:

<blockquote>
<syntaxhighlight lang=bash>
UUID=xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx /               ext4    noatime,data=writeback,errors=remount-ro 0       1
</syntaxhighlight>
</blockquote>

==TRIM==

The TRIM function prepares (wipes) free space and prevents significant slowdown of writes as the drive is used.

===Manual TRIM===

<syntaxhighlight lang=bash>
sudo fstrim -v /
</syntaxhighlight>

Tip: use this tool to TRIM for example every 30 minutes using crontab. See [[MySQL#Schedule_a_backup_with_crontab]] for an example.

===Discard TRIM===

'''Note: this method will cause trimming with every deletion and can slowdown deletions.'''

<syntaxhighlight lang=bash>
sudo gedit /etc/fstab
</syntaxhighlight>

Notice the location of '''discard,''', do not change anything other:

<blockquote>
<syntaxhighlight lang=bash>
UUID=xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx /               ext4    noatime,discard,data=writeback,errors=remount-ro 0       1
</syntaxhighlight>
</blockquote>

Reboot. To test if TRIM is working look here:

* http://askubuntu.com/questions/18903/how-to-enable-trim

==Swap==
	
Lower the likelyness of swap

<syntaxhighlight lang=bash>	
sudo gedit /etc/sysctl.conf

# add/edit these lines

# minimum swappiness
vm.swappiness=0

# weak inode cache schrinking
vm.vfs_cache_pressure=50
</syntaxhighlight>

See also
* [[Ubuntu freezing with high memory usage]]

==I/O scheduler==

Change I/O scheduler strategy to "noop" (or "deadline")

Note: there are alternatives to add this option to grub or to install a "sysutils" package

<syntaxhighlight lang=bash>
cat /sys/block/sda/queue/scheduler 
</syntaxhighlight>	
noop anticipatory deadline [cfq]

<syntaxhighlight lang=bash>	
sudo gedit /etc/rc.local
</syntaxhighlight>	

Add these lines before exit 0 for drive "sda"

<syntaxhighlight lang=bash>	
echo noop > /sys/block/sda/queue/scheduler
</syntaxhighlight>	

Reboot

==Temporary files==

Use in-memory disk for temporary files to reduce the number of writes to the SSD.

<syntaxhighlight lang=bash>
sudo gedit /etc/fstab
</syntaxhighlight>

Add after the last line (exact text)

 tmpfs   /tmp  tmpfs  nodev,nosuid,noexec,mode=1777  0 0

After reboot, using df you should see a line like

<syntaxhighlight lang=bash>
df
...
tmpfs xxxxxx yyyyy zzzzzz n% /tmp
...
</syntaxhighlight>

'''Move firefox cache to the in-memory disk /tmp'''

In Firefox go to url "about:config"

* Look for the setting "browser.cache.disk.parent_directory"
* Create this setting as a New String if it does not exist.
* Set the value to "/tmp".
* Restart Firefox
* Folders as "/tmp/Cash/0", "/tmp/Cash/1", "/tmp/Cash/2" etc will be created by Firefox.

==Zeitgeist==

Zeitgeist is an activity logger that regularly writes to a database in your home folder. The following will prevent this without removing this functionality for all users:

<syntaxhighlight lang=bash>
rm ~/.local/share/zeitgeist/activity.sqlite
</syntaxhighlight>

The file will be recreated and be almost empty, then:

<syntaxhighlight lang=bash>
chmod -rw ~/.local/share/zeitgeist/activity.sqlite
zeitgeist-daemon --replace
</syntaxhighlight>

To enable again do:

<syntaxhighlight lang=bash>
chmod +rw ~/.local/share/zeitgeist/activity.sqlite
zeitgeist-daemon --replace
</syntaxhighlight>

==Monitor I/O activity==

To monitor I/O activity, user left/right to change sort order:

<syntaxhighlight lang=bash>
sudo apt-get install iotop
sudo iotop -a
</syntaxhighlight>

Monitor files open for writing, in this example:
* firefox
* zeitgeist

<syntaxhighlight lang=bash>
sudo lsof -c firefox -c zeitgeist -r 5 | grep -e "[[:digit:]]\+w"
</syntaxhighlight>

==Startup problems without journal==

Note: not needed if you do not turn of the journal.

Did this from other Ubuntu and then it booted

* http://blog.smartlogicsolutions.com/2009/06/04/mount-options-to-improve-ext4-file-system-performance/

<syntaxhighlight lang=bash>
sudo tune2fs -o journal_data_writeback /dev/sdb1
</syntaxhighlight>

Moved aMule and Vuze folders to Data drive, NB: aMule will reset the folder when it is not found