The Oracle ZFS Storage Appliance supports cooperative clustering of appliances. This strategy can be part of an integrated approach to availability enhancement that may also include client-side load balancing, proper site planning, proactive and reactive maintenance and repair, and the single-appliance hardware redundancy built into all Oracle ZFS Storage Appliances.
The clustering feature relies on shared access to storage resources. To configure clustering, both heads must be the same model. Note that the 7420 (with 2Ghz or 2.40GHz CPUs) is based on the same platform and can be clustered with the 7420 (with 1.86GHz or 2.00GHz CPUs).