newfs returns cg 0: bad magic number

[Konstantin Belousov]

On Wed, Jul 05, 2017 at 02:00:43AM +0200, Willem Jan Withagen wrote:
> Hi,
> 
> I'm able to create a Ceph RBD backed ggate disk, in /dev/ggate0.
> It looks like I can:
> 	run dd on it
> 	gpart the disk
> 	create a zpool on it
> 
> But when I try to create a UFS file system on it, newfs complains
> straight from the bat.
> 
> # sudo newfs -E /dev/ggate0p1
> /dev/ggate0p1: 1022.0MB (2093056 sectors) block size 32768, fragment
> size 4096
>         using 4 cylinder groups of 255.53MB, 8177 blks, 32768 inodes.
> Erasing sectors [128...2093055]
> super-block backups (for fsck_ffs -b #) at:
>  192, 523520, 1046848, 1570176
> cg 0: bad magic number
> 
> Googling returns that this is on and off a problem with new devices, but
> there is no generic suggestion on how to debug this....
> 
> Any/all suggestions are welcome,
Typically this error means that the drive returns wrong data, not the
bytes that were written to it and expected to be read.