1. A system, comprising: a first computer cluster node including a first filesystem data storage system; a second computer cluster node coupled with the first computer cluster node and including a second filesystem data storage system; a common filesystem metadata that is configured to be shared by the first computer cluster node and the second computer cluster node; wherein the first computer cluster node and the second computer cluster node are associated with a cluster for shared storage; wherein the common filesystem metadata is structured as a tree having a root node, a plurality of intermediate nodes, a plurality of leaf nodes, wherein the root node and each intermediate node are replicated across the first computer cluster node and the second computer cluster node and stored in their respective filesystem data storage system, wherein each of the plurality of leaf nodes resides only on one computer cluster node; wherein the tree includes one or more subtrees, with a top level of the tree maintained on a parent computer node, which determines whether each of the one or more subtrees is migrated from one node to another node based at least in part on a migration policy, wherein the migration policy tends toward a self-balancing tree.