A method, non-transitory computer readable medium, and device that assists with reducing memory fragmentation in solid state devices includes identifying an allocation area within an address range to write data from a cache. Next, the identified allocation area is determined for including previously stored data. The previously stored data is read from the identified allocation area when it is determined that the identified allocation area comprises previously stored data. Next, both the write data from the cache and the read previously stored data are written back into the identified allocation area sequentially through the address range.