[dm-devel] dm-cache performance behaviour

[Kent Overstreet]

On Tue, Apr 05, 2016 at 12:12:27PM -0400, Mike Snitzer wrote:
> Anyway, as Zdenek effectively: said dm-cache isn't a writecache.  If you
> need a writecache then bcache is the only option as of now.  Though
> there is an emerging DM writecache target that has stalled but can be
> revisited, see:
> http://git.kernel.org/cgit/linux/kernel/git/snitzer/linux.git/log/?h=writecache

bcache is still more than that, it's a combined read/writeback cache :) much
like how today we only have one pagecache for both read caching and write
caching. Main trick is you need a pretty sophisticated btree to pull that off
with good performance.