Which two features are only supported by VMFS6 datastores?

The correct answer highlights a key feature of VMFS6 datastores: support for 4K native storage devices. VMFS6 introduced enhancements to better accommodate modern storage technology, particularly those utilizing 4K sector sizes. This is significant as it allows the file system to work more efficiently with newer drives that are designed to optimize performance and storage efficiency, ensuring greater compatibility and utilization of these drives' capabilities.

Moreover, the support for 4K native storage devices is essential for maximizing the performance of applications running in virtual machines, as these devices are becoming increasingly common in enterprise environments. This includes support for the storage device performance improvements, which can directly influence the efficiency of virtualized environments.

While dynamic expansion and automatic space reclamation are indeed features of VMFS6, they do not specifically pertain exclusively to VMFS6, as some other versions may also support similar functionalities. Therefore, 4K native storage device support is a distinctive feature that sets VMFS6 apart and is crucial for using modern storage solutions in VMware environments.