To attach block storage to a virtual machine for a business-critical application, which protocol should be used for performance?

To attach block storage to a virtual machine for a business-critical application, which protocol should be used for performance?

• A. Using NFS
• B. Using CIFS
• C. Using IPv6
• D. Using iSCSI

Answer: (D)

Block-level storage access provides the best performance for performance-sensitive workloads because the guest OS talks to a raw disk device, not just a shared file. iSCSI carries SCSI commands over TCP/IP, so the VM sees a remote LUN as if it were a local block device. This minimizes overhead, reduces latency, and lets you optimize with features like multipath I/O for redundancy and throughput. NFS and CIFS are file-based protocols; they expose a shared filesystem over the network, which adds metadata handling and locking that can introduce more latency and contention for block-oriented workloads. IPv6 is only a network addressing protocol and doesn’t define storage access semantics. For attaching block storage to a VM with strong performance, iSCSI is the best choice.

Block-level storage access provides the best performance for performance-sensitive workloads because the guest OS talks to a raw disk device, not just a shared file. iSCSI carries SCSI commands over TCP/IP, so the VM sees a remote LUN as if it were a local block device. This minimizes overhead, reduces latency, and lets you optimize with features like multipath I/O for redundancy and throughput. NFS and CIFS are file-based protocols; they expose a shared filesystem over the network, which adds metadata handling and locking that can introduce more latency and contention for block-oriented workloads. IPv6 is only a network addressing protocol and doesn’t define storage access semantics. For attaching block storage to a VM with strong performance, iSCSI is the best choice.