'zfs send -i': destination has been modified

[Dan Langille]

I am trying to do a 'zfs send -i' and failing.

This is my simple proof of concept test:

Create the data
# zfs create storage/a
# touch /storage/a/1
# touch /storage/a/2
# touch /storage/a/3

Snapshot
# zfs snapshot storage/a at 2010.10.19

send
# zfs send storage/a at 2010.10.19 | zfs receive -v storage/compressed/a
receiving full stream of storage/a at 2010.10.19 into
storage/compressed/a at 2010.10.19
received 252KB stream in 2 seconds (126KB/sec)
#



Create one more file and snapshot that

# touch /storage/a/4
# zfs snapshot storage/a at 2010.10.20


send it

# zfs send -i storage/a at 2010.10.19  storage/a at 2010.10.20 | zfs receive -v
storage/compressed/a
receiving incremental stream of storage/a at 2010.10.20 into
storage/compressed/a at 2010.10.20
received 250KB stream in 3 seconds (83.4KB/sec)

What do we have?

# find /storage/compressed/a
/storage/compressed/a
/storage/compressed/a/1
/storage/compressed/a/2
/storage/compressed/a/3
/storage/compressed/a/4


Of note:

* FreeBSD 8.1-STABLE
* ZFS filesystem version 4.
* ZFS pool version 15.
* zfs send is on compression off
* zfs receive has compression on

What I actually want to do and what fails:


# zfs snapshot storage/bacula at 2010.10.19

# zfs send storage/bacula at 2010.10.19 | zfs receive -v
storage/compressed/bacula
receiving full stream of storage/bacula at 2010.10.19 into
storage/compressed/bacula at 2010.10.19
received 4.38TB stream in 42490 seconds (108MB/sec)

# zfs snapshot storage/bacula at 2010.10.20

# zfs send -i storage/bacula at 2010.10.19 storage/bacula at 2010.10.20 | zfs
receive -v storage/compressed/bacula
receiving incremental stream of storage/bacula at 2010.10.20 into
storage/compressed/bacula at 2010.10.20
cannot receive incremental stream: destination storage/compressed/bacula
has been modified
since most recent snapshot
warning: cannot send 'storage/bacula at 2010.10.20': Broken pipe

I have no idea why this fails.  Clues please?

To my knowledge, the destination has not been written to.


-- 
Dan Langille -- http://langille.org/