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Considerations for sharing private layer 2 networks

Starting with ONTAP 9.6, MetroCluster IP configurations with supported Cisco switches can share existing networks for ISLs, rather than using dedicated MetroCluster ISLs. Earlier ONTAP versions require dedicated ISLs.

MetroCluster IP switches are dedicated to the MetroCluster configuration and cannot be shared. Therefore, a set of MetroCluster IP switches can only connect one MetroCluster configuration. Only the MetroCluster ISL ports on the MetroCluster IP switches can connect to the shared switches.

CAUTION
If using a shared network, the customer is responsible for meeting the MetroCluster network requirements in the shared network.
  • MetroCluster ISL requirements in shared networks
    When sharing ISL traffic in a shared network, you must ensure that you have adequate capacity and size the ISLs appropriately. Low latency is critical for replication of data between the MetroCluster sites. Latency issues on these connections can impact client I/O.
  • ISL cabling requirements
    When using shared ISLs in a MetroCluster IP configuration, you must be aware of the requirements for the end-to-end MetroCluster ISL running from controller ports on site A to controller ports on site B.
  • Required settings on intermediate switches
    When sharing ISL traffic in a shared network, the configuration of the intermediate switches provided by the customer must ensure that the MetroCluster traffic (RDMA and storage) meets the required service levels across the entire path between the MetroCluster sites.
  • Examples of MetroCluster network topologies
    Starting with ONTAP 9.6, some shared ISL network configurations are supported for MetroCluster IP configurations.