A fast NAS response to requests isn't the only governing factor to how well workloads perform. Network design, available bandwidth and latency are also important factors. For example, for high-performance NAS applications, where possible, use of a dedicated VLAN for storage is a must. Configuring all components in the storage path to use MTU 9000 will greatly increase throughput by reducing the effects of round-trip network latency and reducing the interrupt load on the NAS server itself. Interrupts are often overlooked as a source of overhead, because they aren't readily measured, but their effects can be significant, both on the NAS server and workload servers. Configure any NAS requiring the highest level of performance for MTU 9000 along with the switching ports used between the NAS host and workload servers.
- Network Throughput - A single 1 GbE network segment will, at most, produce up to 120 MB/sec throughput under the most ideal conditions possible. 10 GbE has been observed to deliver up to 1,000 MB/sec of throughput.
- Network Protocol - Use NFS, CIFS or iSCSI? The iSCSI protocol often provides the best throughput, and increased resiliency through multi-pathing. Just be aware of the added complexities associated with iSCSI.
- For VM-based workloads - it's hard to go wrong with NFS or iSCSI. For user data (e.g.,file shares), CIFS is more common because of the need to integrate natively with Windows, domain controllers and Active Directory when using a NAS as a file server.
- Thick-provisioning VMware data-stores provides increased write performance, and should be preferred over thin-provisioning of VMDKs when optimal performance is required.
- Regardless of design, verify each implementation by running performance benchmarks to validate the throughput expected before going into production.