While I'm sure some of those settings were selected with good reason,
maybe there can be a few options (2 or 3) that have some basic
intelligence at creation to pick a more sane option.

Some checks to see if an option or two might be better suited for the
fs. Like the RAID5 stripe size. Leave the default as is, but maybe a
quick speed test to automatically choose from a handful of the most
common values. If they fail or nothing better is found, then apply the
default value just like it would now.


On Mon, Sep 1, 2014 at 9:22 PM, Christoph Hellwig [off-list ref] wrote:

On Tue, Sep 02, 2014 at 10:08:22AM +1000, Dave Chinner wrote:

quoted

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..
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