A node is coupled to receive a coherency command and coupled to a memory, wherein the node includes a directory configured to track a state of a first number of coherency blocks less than a total number of the coherency blocks in the memory. The directory is configured to allocate a first entry to track the state of the first coherency block responsive to the coherency command. If the first entry is currently tracking the state of a second coherency block, the second node is configured to generate one or more coherency commands to invalidate the second coherency block in a plurality of nodes.