Abstract

iSCSI, NFS, and SMB protocols provide access to storage resources via a TCP/IP network. While iSCSI provides block device access, NFS and SMB are file-level access protocols. In cases where the devices are mounted on the KVM host (as in our case) they could be functionally considered as equivalent when utilized for KVM guest device attachment with image files.

This paper uses iSCSI, NFS, and SMB storage protocols for provisioning KVM guest images in a KVM environment running on IBM Z.

An IBM V7000 provides a common storage back end (or backing store) for each of the storage protocols.

Performance criteria of I/O throughput, I/O CPU cost, KVM guest CPU load, and KVM host CPU load metrics are compared when running a file system workload. Measurements are provided for each storage protocol individually, as well as an overall comparison between protocols.