A host device is coupled to a peripheral device such as a multi media card or the like, where the peripheral device includes a solid state data storage segment. The peripheral device has means for initiating a defragmentation function, such as registers for comparing a current performance measure against a threshold performance metric, or block validity parameters received form the host device for the data storage segment of the peripheral device. Once met, the means for initiating cause a defragmentation function to execute on the data storage segment. A logical layer of the data storage segment is accessed by the host device and a physical layer of the data storage segment is accessed by the peripheral device. The defragmentation program may be resident on either the host or peripheral device. Defragmentation may be enabled to execute automatically once initiated, such as by a continuous or periodic background scan of current performance of the data storage segment.