NetApp Data ONTAP (DOT) 8.1 introduced a lot of new functionalities and optimizations. For me, one of the best ones is introduction of sub-lun cloning when used in conjunction with vStorage APIs for Array Integration (VAAI) for SAN in environments running vSphere 4.1 or higher. The same functionality is available even for Hyper-V through our Power shell and System Center Orchestrator integration.
Originally in case of LUNs, NetApp Virtual Storage Console used the standard copy within the LUN followed by LUN level cloning to achieve fast speeds and space efficiency. Starting 8.0.1, it started to accelerate the cloning with in the LUN using copy offload primitive in VAAI. With 8.1 it took a step further and started utilizing Sub-LUN cloning in environments where both VAAI and FlexClone are enabled to make sure that cloning with in the LUN is space efficient as well.
So what is a Sub-LUN Clone?