Running into this error with just one of the virtual machines - it has a large (500gb) VMDK and I backup using 2gbsparse to NFS.
Debug mode on script gave me the /sbin/vmkfstools command being run.
Ran the command myself, and got this output:
Destination disk format: sparse with 2GB maximum extent size
Cloning disk '/vmfs/volumes/mine/not/yours.vmdk'...
Failed to clone disk: Reached the host's limit for open files (40).
So far have not been able to find out how to raise this limit.
i have exactly the same problem
i try to put this in my crontab : ulimit -n 4096
like that :
* 2 * * * ulimit -n 4096 ; /opt/ghettovcb/bin/ghettoVCB-backup.sh -f /etc/ghettovcb/vmlist -g /etc/ghettovcb/backup.conf
and it's work fine