Re: Cant mount xfs lvm. Experimental Features?

[Dave Chinner <david@fromorbit.com>]

On Wed, Aug 26, 2015 at 01:02:58AM +0200, Marko Weber|8000 wrote:
> Am 2015-08-26 00:58, schrieb Eric Sandeen:
> >On 8/25/15 5:53 PM, Marko Weber|8000 wrote:
> >
> >>eric,
> >>i rebootet the machine and created a new logical volume.
> >>i formatted the lv with mkfs.xfs
> >>i tried to mount it on the new kernel:
> >>
> >>Aug 26 00:47:17 backupserver kernel: XFS (dm-2): Version 5
> >>superblock detected. This kernel has EXPERIMENTAL support
> >>enabled!
> >>Aug 26 00:47:17 backupserver kernel: Use of these features in
> >>this kernel is at your own risk!
> >>Aug 26 00:47:17 backupserver kernel: XFS (dm-2): Superblock has
> >>unknown read-only compatible features (0x1) enabled.
> >>Aug 26 00:47:17 backupserver kernel: XFS (dm-2): Attempted to
> >>mount read-only compatible filesystem read-write.
> >>Aug 26 00:47:17 backupserver kernel: Filesystem can only be
> >>safely mounted read only.
> >>Aug 26 00:47:17 backupserver kernel: XFS (dm-2): SB validate
> >>failed with error 22.
> >l
> >http://xfs.org/index.php/XFS_FAQ#Q:_What_information_should_I_include_when_reporting_a_problem.3F
> >...
> >
> >>this happens with the newly created logical volume.
> >>
> >>the other 2 lvm partitions with xfs are fine.
> >>
> >>any idea?
> >
> >Without any actual information (i.e. kernel versions or userspace
> >version),
> >I'll have to assume that you have recent xfsprogs which sets some
> >features by
> >default which older kernels cannot understand.
> 
> ok, what info do you need?
> 
> on gentoo-linux:
> 
> xfsprogs: v 3.2.4 (Useflag, nls readline)
> kernel:   3.14.51

Kernel is too old for finobt=1, and really too old for CRCs to be
enabled (not fully supported until 3.16).

So, either:

> >mkfs.xfs with -m crc=0,finobt=0 to turn off these features if you have
> >an older kernel which
> >doesn't understand them.

or upgrade your kernel.

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com

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