System error: can't create pivot_root dir

Hi,

I’ve got stardog running on an Ubuntu 15.04 container. After a period over a week or so of normal operation I have had the following exception occur twice now.

Cannot start container f8fc55f1872cd72f1eaad8be57ed5536172d55d1a80fae46812a91d1a022cf77: [8] System error: can’t create pivot_root dir , error mkdir /var/lib/docker/devicemapper/mnt/f8fc55f1872cd72f1eaad8be57ed5536172d55d1a80fae46812a91d1a022cf77/rootfs/.pivot_root580962379: no space left on device

Any ideas as to what causes this error and how to resolve it?

Thanks
Alex