Performance impact of mkfs.xfs vs mkfs.xfs -f

[Martin Steigerwald]

Am Mittwoch, 26. August 2015, 11:09:23 schrieb Dave Chinner:
> On Wed, Aug 26, 2015 at 02:39:11AM +0200, Carlos E. R. wrote:
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> > 
> > On 2015-08-26 01:43, Dave Chinner wrote:
> > > On Tue, Aug 25, 2015 at 04:09:33PM -0700, Shrinand Javadekar
> > > 
> > > wrote:
> > >> Formatted the new disks with mkfs.xfs. Ran the workload.
> > >> Reformatted the disks with mkfs.xfs -f. Ran the workload.
> > > 
> > > Anyway, please post the output so we can see the differences for
> > > ourselves. What we need is mkfs output in both cases, and xfs_info
> > > 
> > >  output in both cases after mount.
> > 
> > Suggestion (for the OP):
> > 
> > To reformat a third time without "-f", you can reformat as ext4, then
> > format a second time as xfs.
> 
> That doesn't work - mkfs.xfs detects that the device has an ext4
> filesystem on it, and demands you use -f to overwrite it.
> 
> > But to imitate a new disk, you have to
> > zero it with dd.
> 
> Only the first MB or so - enough for blkid not to be able to see a
> filesystem signature on it.

wipefs command.

Thanks,
-- 
Martin