[ZFS] Empty shapshot diffs

[Ruslan Makhmatkhanov]

Hello,

there is standard dataset with a bunch of snapshots:

root at sys:~ # zfs list -rt snapshot 
storage03/disks/f0878a5b0a3546e99fa33ba3f0b5476c
NAME                                                              USED 
AVAIL  REFER  MOUNTPOINT
storage03/disks/f0878a5b0a3546e99fa33ba3f0b5476c at 20190423000010  37,6M 
    -  43,7G  -
storage03/disks/f0878a5b0a3546e99fa33ba3f0b5476c at 20190424000707  40,6M 
    -  43,7G  -
storage03/disks/f0878a5b0a3546e99fa33ba3f0b5476c at 20190425001008  39,9M 
    -  43,7G  -
storage03/disks/f0878a5b0a3546e99fa33ba3f0b5476c at 20190426001139   212M 
    -  43,7G  -
storage03/disks/f0878a5b0a3546e99fa33ba3f0b5476c at 20190427001036  69,8M 
    -  43,7G  -
storage03/disks/f0878a5b0a3546e99fa33ba3f0b5476c at 20190428000245  40,4M 
    -  43,7G  -
storage03/disks/f0878a5b0a3546e99fa33ba3f0b5476c at 20190429000715  64,0M 
    -  43,6G  -
storage03/disks/f0878a5b0a3546e99fa33ba3f0b5476c at 20190430001449  38,2M 
    -  43,7G  -
storage03/disks/f0878a5b0a3546e99fa33ba3f0b5476c at 20190501000943  32,2M 
    -  43,7G  -
storage03/disks/f0878a5b0a3546e99fa33ba3f0b5476c at 20190502001414  34,7M 
    -  43,7G  -

But diffing of these snapshots shows nothing:

root at sys:~ # zfs diff 
storage03/disks/f0878a5b0a3546e99fa33ba3f0b5476c at 20190423000010 
storage03/disks/f0878a5b0a3546e99fa33ba3f0b5476c at 20190428000245
root at sys:~ #

More old snapshots of this dataset can be diffed successfully:

root at sys:~ # zfs diff 
storage03/disks/f0878a5b0a3546e99fa33ba3f0b5476c at 20181130000342 
storage03/disks/f0878a5b0a3546e99fa33ba3f0b5476c at 20190507000343
M	/storage03/disks/f0878a5b0a3546e99fa33ba3f0b5476c/
-	/storage03/disks/f0878a5b0a3546e99fa33ba3f0b5476c/disk
+	/storage03/disks/f0878a5b0a3546e99fa33ba3f0b5476c/disk

Any suggestions what can it be and how to debug/fix that?

FreeBSD 11.0-RELEASE-p1 #0 r306420: Thu Sep 29 01:43:23 UTC 2016 
root at releng2.nyi.freebsd.org:/usr/obj/usr/src/sys/GENERIC  amd64

-- 
Regards,
Ruslan

T.O.S. Of Reality