UCS storage physical connectivity has a slightly different design consideration as compared to LAN physical connectivity.

The following are some design considerations for SAN connectivity:

• Northbound storage physical connectivity does not support vPCs like LAN connectivity, where you can have cross-connected vPCs for redundancy.
• Depending on the storage type, port channeling or trunking is possible to combine multiple storage uplink ports that provide physical link redundancy.
• Redundancy of storage resources is handled by the storage itself and varies from vendor to vendor including active-active, active-passive, Asymmetric Logical Unit Assignment (ALUA), and vendor specific implantations such as EMC PowerPath.
• Storage can be connected through northbound Cisco Nexus, MDS or third-party fabric switches. This is the recommended configuration for better scalability and performance.
• It is possible to connect storage directly to UCS Fabric Interconnects, which is recommended for small implementations because of FI's physical ports consumption and increased processing requirements. Prior to UCSM Version 2.1, it was necessary to have a northbound Nexus or MDS switch to provide zoning configuration.
• Software configuration including VSANs and zoning is required for providing access to storage resources.

The following diagram provides an overview of storage connectivity. In the following sections, we will go through various storage configurations: