Sunday, 29 April 2018

How to Convert to a 2-node Switchless Cluster

After spending a little bit of time with the official process to convert a NetApp (Clustered) ONTAP cluster to switchless cluster -

Transitioning to a two-node switchless cluster

- and encountering strange issues (cluster unexpectedly going out-of-quorum), I decided to do it my way (which is better - quicker and simpler - by the way). This is a very simple 9-step step-by-step process.

Image: Starting point: Using 2 cluster switches

1) Cluster checks

Verify the cluster is healthy from the outputs of the below. Cluster LIFs should be on their home ports and should be able to auto-revert. The cluster should be healthy and ping-cluster should be all good. Check discovered-devices/CDPD to ensure the cluster cabling is correct.


set -priv advanced
network options switchless-cluster show
network interface show -role cluster
network interface show -role cluster -fields auto-revert
network port show -role cluster
cluster show
cluster ping-cluster -node {CLUSTER-01}
network device-discovery show


2) Send ASUPs


system node autosupport invoke -node * -type all -message "MAINT=1h BEGIN: Convert to switchless"


3) Wait for the ASUPs to go


system node autosupport history show -node CLUSTER-01
system node autosupport history show -node CLUSTER-02


4) Enable switchless-cluster


network options switchless-cluster show
network options switchless-cluster modify -enabled true
network options switchless-cluster show


Note: All this really does is instruct the cluster to only check cluster communication down the direct connect paths, so disabling the full-mesh checking which is only possible with cluster switches.

5) Un-cable cluster ports from cluster switch 1 and direct connect

Image: Using a direct connect cable and Cluster Switch 2

6) Cluster checks

Verify the cluster is healthy. Verify the cluster ports are healthy. Wait for the Cluster LIFs to auto-revert. After the cluster LIFs auto-revert, verify the cluster is healthy. Finally check cluster communication with ping-cluster.


cluster show
network port show -role cluster
network interface show -role cluster
... WAIT for Cluster LIFs to auto-revert ...
network interface show -role cluster
cluster show
cluster ping-cluster -node {CLUSTER-01}


7) Un-cable cluster ports from cluster switch 2 and direct connect

Image: Using two direct connect cables

8) Cluster checks

Verify the cluster is healthy. Verify the cluster ports are healthy. Wait for the Cluster LIFs to auto-revert. After the cluster LIFs auto-revert, verify the cluster is healthy. Finally check cluster communication with ping-cluster.


cluster show
network port show -role cluster
network interface show -role cluster
... WAIT for Cluster LIFs to auto-revert ...
network interface show -role cluster
cluster show
cluster ping-cluster -node {CLUSTER-01}


9) Send ASUPs


system node autosupport invoke -node * -type all -message "MAINT=END FINISHED: Convert to switchless"


THE END

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