New flashcache from facebook and existing FS. how to make friends?

Question

linux

There is an existing fs: /dev/md2, raid5, ext3. I would like to make it cached using flashcache.
Is it possible to do this:
* Change the type of FS to /dev/md2 to raid
* Build flashcache from /dev/md2 + /dev/sde1 (ssd)
* Set the resulting /dev/mdX to type FS ext3
* Mount successfully?
Perhaps I am not expressing myself clearly, the question is actually about whether flashcache will beat the data during such a migration? Does he write something on the HDD partition other than data?

Answer 1

In general, I experimented by making a backup. 15 minutes flight is normal. everything is working

Answer 2

I don’t think that this is possible, in my memory such migrations ended in failure

Answer 3

Here www.gerrit-tamboer.net/using-flashcache-to-speed-up-your-io-on-ubuntu-12-04/ they write that this is possible, but somehow dumb.
Maybe someone has already done this?