Re: Debunking myths about metadata CRC overhead

Ben Myers
2013-06-04T16:20:34Z

Dave,

On Tue, Jun 04, 2013 at 12:53:07PM +1000, Dave Chinner wrote:
> On Mon, Jun 03, 2013 at 11:10:11AM +0200, Emmanuel Florac wrote:
> > Le Mon, 3 Jun 2013 17:44:52 +1000 vous écriviez:
> >
> > > There has been some assertions made recently that metadata CRCs have
> > > too much overhead to always be enabled. So I'll run some quick
> > > benchmarks to demonstrate the "too much overhead" assertions are
> > > completely unfounded.
> >
> > Just a quick question: what is the minimal kernel version and xfsprogs
> > version needed to run xfs with metadata CRC? I'd happily test it on
> > real hardware, I have a couple of storage servers in test in the 40 to
> > 108 TB range.
>
> If the maintainers merge all the patches I send for the 3.10-rc
> series, then the 3.10 release should be stable enough to use for
> testing with data you don't care if you lose.
>
> As for the userspace code - that is still just a patchset. I haven't
> had any feedback from the maintainers about it in the past month, so
> I've got no idea what they are doing with it. I'll post out a new
> version in the next couple of days - it's 50-odd patches by now, so
> it'd be nice to have it in the xfsprogs git tree so people could
> just pull it and build it for testing purposes by the time that 3.10
> releases....

When it is reviewed and adequately tested we'll pull it in. Until then
Emmanuel will need to pull down the patchset. Right now the focus is on
3.10.

-Ben