= SSD installation checklist =
'''IMPORTANT NOTE''': This document was initially written around November 2010 when SSD support was still considered recent in GNU/Linux distributions and Ubuntu in general. Be careful when deciding to apply any of the information it contains.

A few assumptions are made in this list:
 * '''/dev/sda''' is your SSD device
 * Performance is preferred to reliability. Therefore, you backup regularly or use this for non-critical (even expendable) data.
 * You already have a backup of any important data (can't stress this enough).

If you contribute something to this list, please make sure whatever it is has a justification, explanation, reference, or all three.

== Ubuntu 10.10 ==
 * Check for firmware upgrades for your drive and apply any pending.<<BR>>`$ sudo hdparm -I /dev/sda | grep Firmware`<<BR>>`Firmware Revision:  2CV102M3`<<BR>> Bugs [[https://bugs.launchpad.net/ubuntu/+source/lshw/+bug/663349|#663349]] and [[https://bugs.launchpad.net/ubuntu/+source/udev/+bug/672764|#672764]] have been filed about lshw and udev, mark those as affecting you if you wish so. Once you know your firmware version, go to your manufacturer's site:
  * [[http://www.intel.com/go/ssdfirmware/|Intel SSD firmware updates]]
  * [[http://www.runcore.com/content/support/|RunCore SSD firmware updates]]
  & [[http://www.corsair.com/support/faq/solid-state-drives/#answer1 Corsair FAQ on firmware updates]]
  * ...
 * Boot from a Live CD
  * Find out your hard disk information with '''sudo fdisk -l /dev/sda | grep sectors'''. Example output:<<BR>>`255 heads, 63 sectors/track, 4865 cylinders`
  * Partition & format your disk aligning the partition blocksize to the SSD erase block size, with the above information (1 partition, no swap, no journaling ext4):<<BR>>`sudo fdisk -H 255 -S 63 /dev/sda`<<BR>>`sudo mke2fs -t ext4 -O ^has_journal /dev/sda1`<<BR>>
''Warning: formatting without journaling will increase chances of data loss. Use with caution''. Omit the `-O ^has_journal` option otherwise.  The Linux Documentation Project has complete information about [[http://tldp.org/HOWTO/Partition/fdisk_partitioning.html|fdisk partitioning]].
 * Make sure SATA AHCI mode is enabled in BIOS. See [[http://www.techmetica.com/howto/sata-ahci-mode-bios-setting.-what-does-it-do/|SATA AHCI Mode Bios Setting. What Does it do?]]
 * Reboot the the Alternate Ubuntu installer CD, install normally - use manual partitioning though, mounting / to your single partition, accepting warnings about swap not being present.
 * Kernel boot options:
  * Change the I/O scheduler to NOOP:
   * If you only have one disk and it is SSD, and don't use external storage often, just add '''elevator=noop''' to your kernel boot parameters in /etc/default/grub (append to GRUB_CMDLINE_LINUX_DEFAULT). This is also OK if you occasionally use USB sticks.
   * If you have several disks or a mix of SSD and mechanical disks, install the '''sysfsutils''' package and add the following line at the end of '''/etc/sysfs.conf''':<<BR>>`block/sda/queue/scheduler = noop`
   * To change the scheduler without rebooting:<<BR>>`sudo echo noop > /sys/block/sda/queue/scheduler`
 * Disk mounting options (in /etc/fstab):
  * Example mounting line:<<BR>>`UUID=41b6b187-be76-4447-b18b-d39cc744b184 /               ext4    noatime,discard,data=writeback,errors=remount-ro 0       1`
  * Add the '''noatime''' mounting option. The default is '''relatime''' which adds write operations to set the Last Accessed Time attribute to files.
  * Add the '''discard''' mounting option. This controls whether ext4 should issue discard/TRIM commands to the underlying block device when blocks are freed.  This is useful for SSD devices and sparse/thinly-provisioned LUNs, but it is off by default until sufficient testing has been done.
  * Add the '''data=writeback''' mounting option ''if you formatted the disk without journaling''. Otherwise add '''data=ordered''' which sould be a good compromise between full journaling and none at all. See [[http://www.mjmwired.net/kernel/Documentation/filesystems/ext4.txt|Ext4 Filesystem]] documentation for more details.

= Other considerations: =

 * Mount /tmp in ram
  * Use the following line in /etc/fstab and reboot:<<BR>>{{{tmpfs   /tmp  tmpfs  nodev,nosuid,noexec,mode=1777  0 0}}}<<BR>>'''Rationale:''' In the past when SSD controllers had bad wear leveling and limited amounts of writes, mounting anything that was often wrote to (like /tmp) was a good idea. Nowadays it helps with performance but also as some caveats.
       
 * Put the Firefox cache in /tmp (which is in RAM)
  * Type '''about:config''' in the location bar 
  * Find/create this key: '''browser.cache.disk.parent_directory'''. Set it to {{{/tmp}}}
  * Verify the cache location information in '''about:cache''' 

* '''Pros:'''
 * Placing your browser cache in /tmp, and mounting /tmp in RAM is a sure boost to page rendering.
* '''Cons:''' 
 * Do only with at least 4Gb of RAM  
 * Watch for GUI apps (disc burners etc) writing large files to /tmp
 * In multi-user systems if other users are logged in they will have access to your temporary files in /tmp



= Reference links =

 * http://ubuntuforums.org/showthread.php?t=1041524
 * http://www.zdnet.com/blog/perlow/geek-sheet-a-tweakers-guide-to-solid-state-drives-ssds-and-linux/9190
 * http://www.linuxhowtos.org/System/iosched.htm - including information on how to change the I/O scheduler at runtime