Hi there,
If you get "Device or resource busy" when performing VZ tasks like starting, stopping, quota check on Virtuozzo VPS, please make sure there are no open files inside a container root and/or private area (and your current working directory is not inside a container root/private area) by running the following command on the hardware node (assuming there is a problem with the container #101):
# lsof 2> /dev/null | egrep '/vz/root/101| /vz/private/101'
If there are any processes which hold a directory inside a container root/private area - revise and kill them.