Which protocol is commonly used for block storage access in virtualization environments?

Which protocol is commonly used for block storage access in virtualization environments?

• A. NFS
• B. CIFS
• C. iSCSI
• D. SMB

Answer: (C)

Block storage access means presenting raw disks to the host so you can partition and format them just like a local drive. In virtualization, you often want the hypervisor to attach storage as a block device so each VM sees a true disk. iSCSI fits this need by carrying SCSI commands over IP networks, allowing a storage array to expose logical units (LUNs) that the host can attach as block devices. This gives direct, block-level access to storage, which is ideal for VM disk images and performance-sensitive workloads. NFS and SMB/CIFS, on the other hand, are file-level protocols that present remote filesystems rather than raw blocks, so they’re great for sharing files but not the block storage interface relied on by many virtualization workloads. That's why iSCSI is the commonly used protocol for block storage in virtualization environments.

Block storage access means presenting raw disks to the host so you can partition and format them just like a local drive. In virtualization, you often want the hypervisor to attach storage as a block device so each VM sees a true disk.

iSCSI fits this need by carrying SCSI commands over IP networks, allowing a storage array to expose logical units (LUNs) that the host can attach as block devices. This gives direct, block-level access to storage, which is ideal for VM disk images and performance-sensitive workloads. NFS and SMB/CIFS, on the other hand, are file-level protocols that present remote filesystems rather than raw blocks, so they’re great for sharing files but not the block storage interface relied on by many virtualization workloads. That's why iSCSI is the commonly used protocol for block storage in virtualization environments.