Bcache: Caching beyond just RAM

Bcache: Caching beyond just RAM

There's quite a bit of similarity. L2ARC is read-only, for wide random accesses. bcache aims to be read/write. ZFS also separates out its ZIL for writes. If I'm building a ZFS box I'd use a big MLC drive for the L2ARC and a smaller SLC drive for the ZIL as the workloads differ. You could probably set bcache to be read-only and put a filesystem's journal on a different drive if you wanted a more-like-ZFS segregation. bcache has the nice attribute of just being able to pull it and keep running - ZFS isn't usually set up that way. The L2ARC and ZIL have the checksumming today whereas bcache will get to that. Of course, bcache is much more general and useful in situations where ZFS has no relevance. It's good to have chisels and screwdrivers.