How do you assign and manage WWNs and WWPNs in a Fibre Channel SAN?

1 What are WWNs and WWPNs?

WWNs and WWPNs are 64-bit hexadecimal numbers that identify FC devices and ports. A WWN is assigned to a device, such as a host bus adapter (HBA) or a storage array, and is usually hard-coded by the manufacturer. A WWPN is assigned to a port on a device, and can be either hard-coded or dynamically generated. Each WWN and WWPN must be unique in the FC SAN to avoid conflicts and ensure proper routing.

2 How do you assign WWNs and WWPNs?

There are two ways to assign WWNs and WWPNs: by using the factory default values or by using a custom scheme. The factory default values are based on the vendor's name, the device type, and a serial number. For example, a WWN from IBM might start with 50:05:07, followed by the device type and the serial number. The factory default values are usually sufficient for most FC SANs, unless you have a large or complex environment that requires more control over the naming convention.

If you want to use a custom scheme, you need to use a software tool or a command-line interface to change the WWNs and WWPNs of the devices and ports. You can use any hexadecimal values as long as they are unique and do not conflict with the reserved ranges. For example, you can use the first two digits to indicate the location, the next two digits to indicate the device type, and the last four digits to indicate the serial number. However, you need to keep track of the custom scheme and document it for future reference.

3 How do you manage WWNs and WWPNs?

Managing WWNs and WWPNs involves keeping them updated, consistent, and secure. You need to update the WWNs and WWPNs whenever you add, remove, or replace a device or a port in the FC SAN. You also need to ensure that the WWNs and WWPNs are consistent across the FC SAN, especially if you have multiple switches or zones. You can use tools such as Fabric Manager or Device Manager to view and verify the WWNs and WWPNs of the devices and ports.

Another aspect of managing WWNs and WWPNs is securing them from unauthorized access or spoofing. You can use features such as port authentication, port binding, and port locking to restrict the access and communication of the devices and ports based on their WWNs and WWPNs. You can also use encryption and zoning to protect the data traffic between the devices and ports.

4 Why are WWNs and WWPNs important?

WWNs and WWPNs are important because they enable the FC SAN to function properly and efficiently. They allow the devices and ports to identify and locate each other, and to establish logical connections and paths. They also enable the FC SAN to perform tasks such as discovery, configuration, monitoring, troubleshooting, and optimization. Without WWNs and WWPNs, the FC SAN would not be able to recognize and communicate with the devices and ports, and would not be able to provide reliable and high-performance storage services.

5 What are the best practices for WWNs and WWPNs?

To ensure effective assignment and management of WWNs and WWPNs, it is best to use the factory default values unless you have a specific reason to use a custom scheme. If customizing, be sure to document and update it. Avoid changing the WWNs and WWPNs of existing devices and ports unless necessary, as it can disrupt or confuse the FC SAN. Before adding or replacing devices or ports in the FC SAN, check their compatibility and interoperability, as they may have different WWN and WWPN formats or ranges. Utilize tools and features that help you view, verify, update, and secure the WWNs and WWPNs of the devices and ports. Additionally, keep a backup of the WWNs and WWPNs of the devices and ports in case of failure or loss.

6 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?