What is QSFP and Optical SAS?

What is QSFP?

The Quad (4-channel) Small Form-factor Pluggable (often abbreviated as QSFP or QSFP+) is a compact, hot-pluggable transceiver used for data communications applications. It interfaces a network device motherboard (for a switch, router, media converter or similar device) to a fiber optic cable. It is an industry format jointly developed and supported by many network component vendors, supporting data rates from 4x10 Gbit/s. The format specification is evolving to enable higher data rates. 

How to verify a storage system is using QSFP?

Run sysconfig -a if Data ONTAP 8 or node run -node <nodename> sysconfig -a on ONTAP 9.
 

slot 0: SAS Host Adapter 0a (PMC-Sierra PM8001 rev. C, SAS, <UP>)
                Firmware rev:       01.11.06.00
                Base WWN:           5:00a098:00353ed:08
                Phy State:          [0] Enabled, 6.0 Gb/s
                                    [1] Enabled, 6.0 Gb/s
                                    [2] Enabled, 6.0 Gb/s
                                    [3] Enabled, 6.0 Gb/s
                QSFP Vendor:        Molex Inc.      
                QSFP Part Number:   112-00268+A0    
                QSFP Type:          Optical (1490nm DFB) 5m ID:00
                QSFP Serial Number: 93AG13303F1134

What is Optical SAS?

Optical SAS is used to connect SAS shelves. Connections are made using active optical cables with existing QSFP connectors on supported SAS HBAs. Optical SAS cables are available in both multimode and single mode fiber types, and are compatible with existing optical patch panel infrastructure. Data ONTAP 8.1.3 and 8.2.1 or later is required. 

When should optical SAS cables be used?

Optical SAS cables are designed to provide greater flexibility in configurations of storage controllers and associated disk shelves. These cables should be used when placing shelves greater than 10m from the storage controller. Optical SAS cables can also be used in place of FibreBridge 6500N devices in Stretch MetroCluster configurations.

What types of Optical SAS cables are supported?

Optical SAS Cables are of four types:

• Active Optical Cable (AOC)
  • 1m, 2m, 3m, 5m, 15m, 30m, and 50m lengths
  • Cable assemblies with attached QSFP connector
• Multimode Direct Cable Connect
  • For non-standard lengths or connectivity up to 150m
  • QSFP with MPO connector provided, OM4 cable with MPO connectors will need to be procured from vendor
• Multimode Optical Patch Panel Connect
  • Utilizes existing optical patch panels for distances up to 150m with OM4 cable and 100m with OM3
  • Cables available in 5m and 30m lengths
  • Available with LC, SC, or MT-RJ connectors
  • Utilizes QSFP with MPO connector
  • Requires eight patch panel ports per connection
• Single mode Optical Patch Panel Connect
  • Utilizes existing Single mode optical patch panels for distances up to 500m
  • Cables available in 5m and 30m lengths
  • Available with LC, SC, or MT-RJ connectors
  • Attached QSFP connector for HBA connectivity
  • Requires eight patch panel ports per connection 

Can optical SAS cables be used to replace FibreBridges in MetroCluster configurations?

Yes. In stretch MetroCluster configurations optical SAS cables can be used in place of FibreBridge devices.

The following diagrams show examples of multi-mode and single-mode Stretch MetroCluster examples.