MODIFIED I/OS AMONG STORAGE SYSTEM LAYERS

A method of managing I/Os in a storage system between a first storage layer and a second layer which is a logical abstraction over the first storage layer, comprising of maintaining within the first storage layer of the storage system validity status data indicating a validity status of each one of a plurality of first layer storage segments, in response to a write command that includes payload data which relates to part of an invalid segment providing the second layer with an unaligned write to an invalid segment indication, and in response to receiving the indication at the second layer, providing a modified write command for the invalid segment including initial values combined with the payload data.