A large financial institution operates a dual-fabric Fibre Channel SAN with two separate MDS 9710 directors. Each fabric has multiple storage arrays and hundreds of hosts. The SAN is configured with VSANs to isolate different environments (production, development, backup). Recently, the backup VSAN has been experiencing slow performance during backup windows. Analysis shows that the ISLs between the directors in the backup VSAN are heavily utilized (near 100%) while other ISLs have spare capacity. The backup traffic consists of large sequential reads and writes. The SAN administrator has confirmed that there are no CRC errors or link issues. The backup VSAN uses a single 16 Gbps ISL. Which of the following is the best solution to improve backup performance?