Dave Chinner wrote:
> On Mon, Jun 23, 2008 at 09:23:10PM -0500, Eric Sandeen wrote:
>> Maybe there should be a QUEUE_ORDERED_PASSTHRU flag?
>> Or should XFS just stick with the test write and ignore the flag? I'm
>> not sure of the queue->ordered flag details, but it seems that XFS & md
>> raid1 both try hard to keep barriers in force, and there's a disconnect
>> here somewhere.
> Yeah, the problem was that last time this check was removed was
> that a bunch of existing hardware had barriers enabled on them when
> not necessary (e.g. had NVRAM) and they went 5x slower on MD raid1
> Having to change the root drive config on a wide install
> base was considered much more of support pain than leaving the
> check there. I guess that was more of a distro upgrade issue than
> a mainline problem, but that's the history. Hence I think we
> should probably do whatever everyone else is doing here...