A system and method for improving the management of data input and output (I/O) operations for Shingled Magnetic Recording (SMR) devices in a network storage system is disclosed. The storage system includes a storage controller that receives a series of write requests for data blocks to be written to non-sequential addresses within a pool of SMR devices. The storage controller writes the data blocks from the series of write requests to a corresponding sequence of data clusters allocated within a first data cache of the storage controller for a thinly provisioned volume of the pool of SMR devices. Upon determining that a current utilization of the first data cache's data storage capacity exceeds a threshold, the sequence of data clusters including the data blocks from the first data cache are transferred to sequential physical addresses within the SMR devices.