A mega cluster storage system includes clusters of multiple storage modules. Each module is able to access a portion of the data within the mega cluster and serves as a proxy in order for another storage module to access the remaining portion of the data. A cluster is assigned to a unique cluster volume and all the data within the cluster volume is accessible by all of the modules within the cluster. Each host connection to the mega cluster is associated with a particular cluster volume. A module that receives a host I/O request determines whether the I/O request should be satisfied by a module within its own cluster or be satisfied by a module within a different cluster. The module may forward the I/O request to a module within a different cluster as indicated by a distribution data structure that is allocated and stored within each storage module.