A file system is disclosed that includes an application wide name space instantiated in a global index (Gindex) that is used for accessing objects related to an application. Using the Gindex, a method for cache coherency includes establishing one or more appliances, each defining a storage cluster; establishing one or more tenants spanning across appliances, wherein an application stores objects in file systems associated with the appliances and tenants; establishing a Gindex including metadata relating to objects stored in association with the application; replicating the Gindex to plurality of data centers supporting the tenants; storing an original object at a first data center; storing a cached copy of the object at a second data center; aligning the cached copy using metadata for the object from a local copy of the Gindex.