Re: XFS reflink vs ThinLVM

On 13/01/20 17:53, Darrick J. Wong wrote:

mkfs.xfs -d extszinherit=NNN is what you want here.

Hi Darrik, thank you, I missed that option.

Right.

Ok

xfs_bmap -c, but only if you have xfs debugging enabled.

[root@neutron xfs]# xfs_bmap -c test.img
/usr/sbin/xfs_bmap: illegal option -- c
Usage: xfs_bmap [-adelpvV] [-n nx] file...

Maybe my xfs_bmap version is too old:

If you happen to have rmap enabled, you can use the xfs_io fsmap command
to look for 'cow reservation' blocks, since that 124k is (according to
ondisk metadata, anyway) owned by the refcount btree until it gets
remapped into the file on writeback.

I see. By default, on RHEL at least, rmapbt is disabled. As a side note, 
do you suggest enabling it when creating a new fs?

Thanks.

-- 
Danti Gionatan
Supporto Tecnico
Assyoma S.r.l. - www.assyoma.it
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