In virtualized environments, SAN connectivity is very crucial for hypervisors as a shared SAN is a critical component for advanced virtualization features, such as migrating and then running virtual machines between different hosts. A problem with the connectivity of the SAN array can also cause issues with the SAN boot.
SAN could be connected to Fabric Interconnects directly or through a northbound Nexus, MDS, or third-party switch. Proper connectivity between Fabric Interconnects and SAN storage processors or Fabric Interconnects and SAN fabric switches is necessary. SAN connectivity is also configured as redundant. However, unlike Ethernet, where a northbound vPC that is using a cross-switch connection can protect against a complete switch failure, the connectivity between SAN switches and Fabric Interconnects can only be a straight connection. It is, however, possible to create a Fibre Channel port channel for protection against a single port failure if SAN supports it.
Perform the following procedure to look into SAN connectivity (the screenshot is showing direct attached FCoE storage):
- Log in to UCS Manager.
- Click on the SAN tab in the navigation pane.
- In the SAN tab, expand the Fabric Interconnects in the Storage Cloud expand list.
- Expand Storage FCoE Interfaces, and the status of the SAN connectivity will be shown in the work pane as follows:
- The following screenshot shows a port connectivity issue in the form of membership-down; this means that the physical connectivity between the Fabric Interconnect and its storage is down:
In order to mitigate the risk of Fibre Channel single link failures, Fibre Channel port channels or trunking can be established to ensure uninterrupted connectivity. Refer to Chapter 6, Configuring SAN Connectivity, which discusses the procedure for the creation of a Fibre Channel port channel for storage connectivity.