A database manager maintains a database including information tracking a set of storage units and a set of storage appliances on which the storage units currently reside. At least a portion of the tracking information is cached in a server cache at a namespace redirection server. Some of the tracking information is cached in a set of client caches at a set of clients. A request to access a storage unit is received at a client. A lookup is made into a client cache at the client to find a storage appliance having the storage unit. A determination is made that there is a problem accessing the storage unit using the client cache. So, the namespace redirection server is queried for updated tracking information concerning a location of the storage unit. The client assists the namespace redirection server with management of the server cache.