As an extension of the national Grid project METACentrum, run by CESNET, two Grid
farms are to large extent dedicated to the particle physics applicatio ns. We will
describe the hardware installed on both farms, how the farms are connected into the
large Grid infrastructure (Grid projects LCG and EGEE) and provide an overview how
the computing facility is shared between different projects, so that concurrent
interoperability of all the installed software and infrastructure can be assured.