On Tue, Sep 02, 2014 at 10:08:22AM +1000, Dave Chinner wrote: > Pretty obvious difference: avgrq-sz. btrfs is doing 512k IOs, ext4 > and XFS are doing is doing 128k IOs because that's the default block > device readahead size. 'blockdev --setra 1024 /dev/sdd' before > mounting the filesystem will probably fix it. Btw, it's really getting time to make Linux storage fs work out the box. There's way to many things that are stupid by default and we require everyone to fix up manually: - the ridiculously low max_sectors default - the very small max readahead size - replacing cfq with deadline (or noop) - the too small RAID5 stripe cache size and probably a few I forgot about. It's time to make things perform well out of the box.. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>