Understanding second-level vifs in a cluster

Advantage of second-level vifs in a cluster

In a cluster configuration, you can access data from both storage systems even if one of the storage systems in the cluster fails. In a second-level vif connected in a single-mode configuration, you can maintain connectivity to your storage system even if one of the switches fails. Thus, by using the two configurations together, you can achieve a fully redundant storage system connectivity architecture.

Normal cluster operation with second-level vifs

The following figure shows second-level vifs in a cluster. When both storage systems are in operation, the following connections exist:

Firstlev1 in Secondlev 1 connects StorageSystem 1 to the network through Switch 1.
Firstlev2 in Secondlev 1 connects StorageSystem 1 to Switch 2.
Firstlev4 in Secondlev 2 connects StorageSystem 2 to the network through Switch 2.
Firstlev3 in Secondlev 2 connects StorageSystem 2 to Switch 1.

Firstlev2 and Firstlev3 are in standby mode.

Switch failure in a cluster with second-level vifs

If one of the switches fails, the following happens:

If Switch 1 fails, Firstlev2 and Firstlev4 maintain the connection for their storage systems through Switch 2.
If Switch 2 fails, Firstlev1 and Firstlev3 maintain the connection for their storage systems through Switch 1.

In the following figure, Switch 1 fails in a cluster. Firstlev2 takes over the MAC address of Firstlev1 and maintains the connectivity through Switch 2.