I've got the xenner service running, and every couple of seconds I get this:

blkbackd(2500): dirtied inode 915815 (blkbackd.stats.gJHwxb) on dm-0
netbackd(2511): dirtied inode 915864 (netbackd.stats.mhdnHb) on dm-0

The fun part is the files they're writing to:

# cat /var/run/blkbackd.stats
blkbackd stats

# cat /var/run/netbackd.stats 
netbackd stats

are essentially empty!  So we're writing.. nothing to an inode, making the disk spin and well all the fun that follows from that.  Every couple seconds.

Please to be fixing.