A company has merged its two existing SANs that were in adjacent buildings. The data center in each location had been utilizing at least half of its total SAN bandwidth. Now they now plan to migrate a

No change to SAN performance is unlikely, as the primary SAN's workload has significantly increased due to consolidation and added replication traffic.

Increased performance for production traffic would only occur if the consolidated SAN had vastly underutilized capacity, which contradicts the statement that original SANs were utilizing at least half their bandwidth.

Previously, two separate SANs each handled at least 50% of their respective workloads. After consolidation, all production data and its associated I/O, plus the additional synchronous replication traffic to the disaster recovery site over new ISLs, will be concentrated on a single SAN infrastructure. This significant increase in demand on the primary SAN's resources (HBAs, switches, storage controllers, and backend disks) will likely lead to resource contention and decreased performance for production traffic compared to when the workloads were distributed.

While ISL over-subscription can impact performance, it is a contributing factor. The direct impact is the decreased performance of the production SAN due to the overall increased workload and contention on its resources.