app-nfsd shows no stats

When I netcat the observium-agent of our storage-server I get the following for nfsd:

<<<app-nfsd>>>
rc 0 3262276 11714942
fh 0 0 0 0 0
io 1012421615 1079238768
th 32 0 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
ra 64 0 0 0 0 0 0 0 0 0 0 0
net 14977013 0 14976885 6
rpc 14976901 0 0 0 0
proc2 18 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
proc3 22 0 304 0 18 20 0 0 0 0 0 0 0 0 0 0 0 0 0 20 0 0 0
proc4 2 2 14976465
proc4ops 59 0 0 0 699531 4021436 4346 1438 0 0 13846271 4239317 0 31 0 30 84271 0 0 4366901 0 792334 0 14793981 0 90018 1165970 82534 822 469 11358 13046 4209683 4379447 0 72935 90018 90018 0 2975085 30 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

The problem is that is see no rrd being generated in observium/rrd/storage1/ while I can see rrd's of other metrics. Also there are no graphs visible on the nfsd-page of the storage-machine for nfsd (only titles) while other graphs work fine.