A method, executed by a computer, includes writing, to a storage device, a first instance of a data sequence and a corresponding first reference count, in response to determining that a subsequent data sequence is identical to the first instance of the data sequence, writing, to the storage device, a metadata reference referencing the subsequent data sequence and incrementing the first reference count, and writing, to a storage device, a second instance of the data sequence and a corresponding second reference count in response to determining that the first reference count is equal to a selected threshold. A computer system and computer program product corresponding to the above method are also disclosed herein.