snf-mkimage runs out of space despite very large --tmpdir

[randyqx]

a ubuntu 14.04 64-bit vm. the disk is 8G, 6G used
snf-mkimage 0.9

# snf-mkimage --tmpdir=/NFS -o /NFS/image --print-syspreps /

runs out of disk space
/NFS is a 64G nfs-mounted volume, more than enough room for temp and final 8G images

# df -h
Filesystem     Size  Used Avail Use% Mounted on
/dev/vda1       32G  6.0G   24G  21% /
...
nfs.foo:/NFS    63G  1.7G   59G   3% /NFS

# snf-mkimage --tmpdir=/NFS -o /NFS/image --print-syspreps /
...
Copying files to temporary image: [############################### ] 204835/2060
Copying files to temporary image: [############################### ] 205142/2060
Copying files to temporary image: [############################### ] 205447/2060
22rsync: write failed on "/tmp/tmpejoCM2/var/cache/apt-xapian-index/index.1/spelling.DB": No space left on device (28)
rsync error: error in file IO (code 11) at receiver.c(389) [receiver=3.1.0]
Copying files to temporary image ... done
cleaning up ...
Error: rsync failed

[randyqx]

so i mount the 64g nfs on /tmp

Filesystem           Size  Used Avail Use% Mounted on
/dev/vda1             32G  6.0G   24G  21% /
nfs.foo:/NFS         63G  1.8G   58G   3% /tmp

and do not specity --tmpdir.

# snf-mkimage -o /tmp/netsrv.diskdump --print-syspreps /

to no avail

Copying files to temporary image: [################                ] 106042/2060Copying files to temporary image: [################                ] 106171/2060Copying files to temporary image: [################                ] 106384/206095rsync: write failed on "/tmp/tmpMyNe9N/export/var/tmp/.snf_image_creator.UGXgtr/946c38026b9a46a5a18fc83e92f3f635.raw": No space left on device (28)
rsync error: error in file IO (code 11) at receiver.c(389) [receiver=3.1.0]
Copying files to temporary image ... done
cleaning up ...
Error: rsync failed