[linux-lvm] How does LVM-Cache work?

[thornber at redhat.com]

On Tue, Feb 26, 2013 at 03:44:43PM -0300, Leo Antonio wrote:
> Hello, everyone.
> 
> I'm willing to do research about second-level cache using SSDs and I think
> that the best way to do this is using LVM/Device Mapper, because other
> implementations are based on FUSE, virtualization layers, and others.
> 
> What I'm trying to do is to develop a subsystem that will put hot
> blocks/PEs on SSDs-Cache, as well as group related blocks/PEs on cache
> automatically. Not simply put on SSD the most  used files or directories.
> 
> The problem is that I could not find any documentation about DM or LVM to
> help my research and development.
> 
> Could you point me to some documentation or what's the best way to
> accomplish this?

See my dm-cache target in this branch of my tree:

https://github.com/jthornber/linux-2.6/tree/thin-dev

https://github.com/jthornber/linux-2.6/blob/thin-dev/drivers/md/dm-cache-target.c

There's still a lot of work to do on the policy plug-ins, so if you
like to get involved that would be great.

- Joe