Flashcache
  * data stored on main storage
  * flashcache is layer in between mysql and stable storage
  * runs on SSD
  * developed by facebook
  * kernel module -> works on device, IO level
  * they have some outdated binaries on percona site

supports both write-through and write-back

insert kernel module, then create a partition for cache (that is backed by stable storage?)
  * oh, define a percentage, of how much to be stored in cache vs. main storage

maybe doesn't work for everything
  * mysqldump will trash the cache
  * lvm snapshot can't handle layout
  * he likes percona xtrabackup in this situation

full table scan queries will trash cache
  * FB has patch where you can do select, and specify not to use cache

create filesystem, mkfs it, and then layer flashcache on top of that
  * flashcache plugs in using devicemapper

can use any block device for flash cache (faster SAS disks, for example)