ssd caching setup for ubuntu

instructions

= ssd cache setup=
I got a new pc with an SSD and a spinner disk. Having to decide exactly what I think I needed on the SSD was hard. Why not try using it as a caching device?

==Why use ssd caching?==
* Intel's "Smart Response Technology" on Windows 7 is awesome
* SSD wear can be reduced
* The ssd use can be optimized automagically
* No compromise on free space on ssd vs empty space on hdd

===What runs slow normally for me?===
* git commands with large repos
* database restores, installs, and bulk changes

==Caching software options:==
* no linux driver for Intel SRT
* flashcache - by Facebook
* dm-cache
* bcache

===Why flashcache?===
* packaged for Ubuntu 13.10
* can be setup without wiping data

==Setup==
===install Ubuntu===
* install Ubuntu on to the hdd, with your preferred partitions
* after install, create ext4 partition on SSD - I used the whole drive
* If you want multiple HDD partitions cached, create a cache partition on the SSD for each one
* don't mount the ssd
===Setup flashcache===
This can be done without needed a fresh install.
* apt-get install flashcache-utils flashcache-dkms
* BACKUP /home partition first (or the other directorys that you want cached)
* logout
* Ctrl + Alt + F1
* Login with your username
* Become root
 sudo su
* set a password for root
 passwd
 exit
 exit
* Login as root. Use root as username and the password you just set
* Stop Lightdm
 service lightdm stop
* Now you can umount /home
 umount /home
* build the flashcache partition
 flashcache_create -p back fcache_home /dev/(MOUNT POINT OF /home) /dev/disk/by-uuid/(UUID OF SSD)
change /etc/fstab so /home uses flashcache
* comment out the current mount point for /home
* add the following lines
 # Flashcache home_cached
 /dev/mapper/fcache_home    /home    ext4    noatime,nodiratime,discard 0 0
* reboot
===Test flashcache===
test flashcache is working
 sudo dmsetup status
 fcache_home: 0 123456789 flashcache stats: ...
see /home mounted to fcache_home
 df -h | grep home
 /dev/mapper/fcache_home    444G    146G    276G    35%    /home
=== Cache some more stuff ===
Oh yeah, I wanted databases cached too!

move the postgres data directory
 sudo mkdir /home/pgdata
 sudo chown postgres:postgres /home/pgdata
 cd /var/lib/postgresql/9.1/main
 mv main main.old
 ln -s /home/pgdata main
 chown -h postgres:postgres main
move the mysql data directory
 sudo mkdir /home/mydata
 sudo chown mysql:root /home/mydata
 cd /var/lib/mysql
 mv mysql mysql.old
 ln -s /home/mydata mysql
 chown -h mysql:root mysql