On Tue, Sep 11, 2012 at 07:12:58PM +0800, ching wrote: > > 1. According to btrfs wiki, defragment a COW file will produce two unrelated files. > > > > Does it apply to the "autodefrag" mount option? > > can anybody helps on question 1? The data blocks associated with the files (that were originally created by snapshotting and thus shared the same blocks) will become unshared, so yes it would appear like two unlreated files. Autodefrag option affects only newly written data. With current implementation it could unshare some extents if the defragged range picked by autodefrag logic overlaps with an existing one. >From my experience, running 'btrfs fi defrag' with autodefrag on produced better result. Beware that there are some unfixed deadlocks that may happen with autodefrag enabled. david -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
