ONTAP Discussions

Cluster Peer Unavailable - Data and ICMP Reachable


Attempting to peer two clusters (Cluster #1 and Cluster #2) but cannot get past Availability = Unavailable


Cluster #1 is a six (6)-node cluster


Cluster #2 is a two (2)-node cluster


Tried peering with and without authentication - current peering has Authentication - OK


Both Data and ICMP Ping status are session_reachable and interface_reachable respectively on both sides of the peering


All ports involved/recognized have the same MTU (9000)


Cluster #1 is currently successfully peered and the source to a 3rd-party provider for DR (SnapMirror)


Cluster #1 displays both nodes for Cluster #2 for Remote Cluster Nodes - output of cluster peer show -instance


Cluster #2 only shows Cluster #1's node1 (of six) in for Remote Cluster Nodes - output of cluster peer show -instance


Cluster #2 DOES, however, show all six IP addresses for each node of Cluster #1 for Active IP Addresses - output of cluster peer show -instance



Re: Cluster Peer Unavailable - Data and ICMP Reachable


So the solution to my problem here was two-fold:


1. Existing Peer relationship between our production ClusterA and our DR provider's ClusterB was configured using ClusterA's DEFAULT IPSpace.  On the advice of NetApp support I created a separate (dedicated) IPSpace for ClusterA to talk to ClusterC.  This means I had to create a new/dedicated IPSpace as well and add a route.


2. MTU sizes.  My downfall here was that my Intercluster LIFs on ClusterA and associated Broadcast domain is set to 9000.  However, I confirmed with our DR provider that the ports/broadcast domain at their end is set to 1500.  So rather than heed all advice I've ever read/seen here I assumed that if mis-matched MTUs worked for the ClusterA-ClusterB peering it should work for ClusterA-ClusterC.  So I only changed ClusterC's broadcast domain and ports to run at MTU 1500.  NO GO.  When I changed my new broadcast domain on ClusterA and associated ports to 1500 the peering worked.

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