Just a few notes as I move to a new SSD. Setting it up correctly from the beginning should help drive performance and longevity.
In /etc/rc.local, add
hdparm -W1a0A0 /dev/sda
From
http://apcmag.com/how-to-maximise-ssd-performance-with-linux.htm
Partition alignment
This can only be done with a
clean system before you install either Linux or Windows. Partition
alignment is critical for SSDs as, being memory-based devices, data is
written and read in blocks known as pages. When partitions aren't
aligned, the block size of filesystem writes isn't aligned to the block
size of the SSD, causing extra overhead as data crosses page boundaries.
Aligning
partitions is simply a matter of ensuring the first partition starts on
a clean 1MB boundary from the start of the disk, ensuring whatever
block size the filesystem uses will align with the block size of the SSD
(which can also vary). If you create partitions using Windows 7 on an
empty drive, it will start partitions at the 1MB boundary automatically.
In
Linux, simply run 'fdisk -cu (device)' on the drive you want to
partition, press 'n' for new partition, 'p' for primary and enter a
start sector of at least 2,048. The general rule is that the starting
sector must be divisible by 512, but to cater for all variations of SSD
page size and filesystem block size, 2,048 is a good idea (and equates
to 1MB).
*Note -- if you use LVM on a bootable partition, grub2 needs to put more code at the beginning of the drive, so you might want to leave even more headroom before the first partition.
Scheduler
For Ubuntu and other distributions using GRUB2, edit the
/etc/default/grub file and add 'deadline' to the
GRUB_CMDLINE_LINUX_DEFAULT line like so:
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash elevator=deadline"
Then run 'sudo update-grub2'.
Applications
Any applications that write excessively to a hard drive are also
candidates for moving data. Browsers are a fine example of this -- the
browser cache is nice, but it'd work just as well from a spinning
platter drive and save your SSD from thousands of writes a day that
don't make a huge difference to you.
To move the cache in
Firefox, in the browser type 'about:config', right-click anywhere and
select New --> String, and add 'browser.cache.disk.parent_directory'.
Edit the variable and point it to a directory on a non-SSD drive or, if
you don't mind losing the cache between boots and you're using the
tweaks above, point it to /tmp for a super-fast memory cache.
Moving
the cache in Chrome is a little harder. The directory is hardcoded, but
you can use symbolic links to point it to a directory on another drive
or to /tmp. You'll find the cache under ~/.cache/chromium. You could
also redirect the entire .cache direct
Applications
ory, as many programs use this for
caching data.
From
http://wiki.freeswitch.org/wiki/SSD_Tuning_for_Linux
Using tmpfs to reduce drive usage
tmpfs /ramdisk tmpfs nodev,nosuid,noatime,mode=1777,size=100M 0 0
tmpfs /tmp tmpfs defaults,noatime,mode=1777 0 0
#tmpfs /var/spool tmpfs defaults,noatime,mode=1777 0 0
tmpfs /var/tmp tmpfs defaults,noatime,mode=1777 0 0
# .thumbnails files are never deleted and can grow quite large over time.
tmpfs /root/.thumbnails tmpfs defaults,noatime,mode=1777 0 0
tmpfs /home/mario/.thumbnails tmpfs defaults,noatime,mode=1777 0 0
*Note -- I removed the /var/spool mount point because it messes up user cron jobs and mail server services.
Swappiness
This only applies if the swap file is moved to the SSD. The
swappiness value affects the activity of the swap file. If you placed
the swap file on the SSD you should
reduce the swappiness of Linux. There are many good explanations but simply put: Linux tries to anticipate when something
might
need to be swapped and does it anyway. By reducing swappiness Linux is
less likely to do this so swap writes are reduced. Swappiness is a value
from 0 to 100, the higher the more swappiness. You can check your
current value using:
cat /proc/sys/vm/swappiness
There are a couple of different ways to change swappiness
permanently. I changed this system from it's default of 60 to 1 by
adding the following to /etc/sysctl.conf:
vm.swappiness=1
vm.vfs_cache_pressure=50
