On Wed, May 9, 2012 at 8:07 PM, Kent Overstreet <koverstreet@xxxxxxxxxx> wrote: > bcache: a cache for arbitrary block devices using an SSD. > > Short overview: > Bcache does both writethrough and writeback caching. It presents itself as a > new block device, a bit like say md. You can cache an arbitrary number of > block devices with a single cache device, and attach and detach things at > runtime - it's quite flexible. > > It's very fast. It uses a b+ tree for the index, along with a journal to > coalesce index updates, and a bunch of other cool tricks like auxiliary binary > search trees with software floating point keys for searching within btree > nodes. > > Bcache is solid, production ready code. There are still bugs being found that > affect specific configurations, but there haven't been any major issues found > in awhile - it's well past time I started working on getting it into mainline. > > It's a lot of code - I tried to split it out so that it'd make some sort of > sense for reviewing. Let me know if there's anything else I can do to make > review easier. > > TODO/known issues: > > __up_write() needs to be exported for bcache to compile as a module - it's > used for bypassing lockdep when traversing the btree during garbage > collection. If someone else knows a better solution, please let me know. > > The userspace interface is going to change before it goes in. The general > consensus at LSF was that we don't want yet another interface for > probing/managing block devices, and dm exists so we may as well use that. I > don't think anyone's started on that yet, though. Might as well mention I've started work on a md conversion. Nearing the point of having RFC patches ready to post. I'm doing it in such a way that it does not preclude a dm target from coming along as well. Like I mentioned to Alasdair at LSF, there's no reason this could not be treated the same as the shared raid personalities between dm and md. -- Dan -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
