"XFS (md8): EXPERIMENTAL online shrink feature in use. Use at your own risk!" message

[rxn123talon]

I have an array of 8 disks of varying sizes.   The 8th disk is a 14TB drive that gives the message "XFS (md8) : EXPERIMENTAL online shrink feature is in use.   Use at your own risk!" when the drive is formatted with XFS.   If I change the format of the drive (I moved all the data off it so it is clear) by stopping the array, changing the format to say reiserfs, restarting the array and allowing it to format... the message doesn't show.   I am only seeing this message if I format the disk to XFS.

 

I am currently running 6.10.0-RC2.   Any ideas?   It doesn't appear to be causing an issue, it's just a concerning message that shows.

[ChatNoir]

REISERFS is not recommended and only available for compatibility reasons.

You should probably attach your diagnostics to your next post.

[rxn123talon]

I was only flipping between file systems to force it to reformat the drive with hopes the message would go away.

 

If I look in dmesg, I see the following ONLY for disk8.  I want to understand why this is only for md8 and none of the others.   It looks like an ominous warning even though everything appears to function fine.

 

root@Deathstar:~# dmesg | grep md8
[  116.577230] md8: running, size: 13672382412 blocks
[  118.259234] md8: stopping
[  225.828873] md8: running, size: 13672382412 blocks
[  229.265795] XFS (md8): Invalid superblock magic number
[  277.632501] XFS (md8): Mounting V5 Filesystem
[  277.790518] XFS (md8): Ending clean mount
[  277.795654] XFS (md8): EXPERIMENTAL online shrink feature in use. Use at your own risk!

deathstar-diagnostics-20220208-1633.zip