I've got a few LVM instances on CentOS which have a device path of /dev/mapper/foo-bar. LVM creates that device name by adding the LV and VG together. Unfortunately, anything with a '-' in the name breaks the graphing. In the resource graph menu, the display of volumes shows as broken (displays variable names instead of values).

Very easy to reproduce. Change ns-dskDevice for that collection to include a -, restart tomcat or reload the page and the graph will break. Remove the -, restart tomcat or reload the page and it will work.