On Wed, 2008-12-17 at 14:24 -0700, Andreas Dilger wrote: > I can't speak for btrfs, but I don't think multiple device access from > the filesystem is a "layering violation" as some people comment. It > is > just a different type of layering. With ZFS there is a distinct layer > that is handling the allocation, redundancy, and transactions (SPA, > DMU) > that is exporting an object interface, and the filesystem (ZPL, or > future > versions of Lustre) is built on top of that object interface.
Clean interfaces aren't really my best talent, but btrfs also layers this out. logical->physical mappings happen in a centralized function, and all of the on disk structures use logical block numbers. The only exception to that rule is the superblock offsets on the device. -chris -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
