Pieter Bowman wrote at 11:41 -0600 on Apr 25, 2008:
 > The final issue I found was that the inode numbers in the snapshots
 > change each time a new snapshot is created.  This is a problem with
 > GNU tar's listed-incremental facility.  To work around this I ended up
 > hacking GNU tar to make it ignore the inodes stored in the listed
 > incremental files.  This was just a simple change, to have ZFS
 > filesystems treated the same as NFS.  The patch was submitted to the
 > GNU tar developers, but was rejected.  Here is the patch as applied to
 > GNU tar 1.16 (this patch also contains what I consider a fix for an
 > actual coding bug):

The gtar devs finally accepted something to help with this problem:
--no-check-device.

http://article.gmane.org/gmane.comp.archivers.amanda.user/32804/match=nfs+tar