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Cluster and storage switches

Replace NVIDIA SN2100 cluster switches with switchless connections

Contributors netapp-pcarriga netapp-jolieg
PDFs

You can migrate from a cluster with a switched cluster network to one where two nodes are directly connected for ONTAP 9.3 and later.

Review requirements

Guidelines

Review the following guidelines:

  • Migrating to a two-node switchless cluster configuration is a nondisruptive operation. Most systems have two dedicated cluster interconnect ports on each node, but you can also use this procedure for systems with a larger number of dedicated cluster interconnect ports on each node, such as four, six or eight.

  • You cannot use the switchless cluster interconnect feature with more than two nodes.

  • If you have an existing two-node cluster that uses cluster interconnect switches and is running ONTAP 9.3 or later, you can replace the switches with direct, back-to-back connections between the nodes.

What you'll need

  • A healthy cluster that consists of two nodes connected by cluster switches. The nodes must be running the same ONTAP release.

  • Each node with the required number of dedicated cluster ports, which provide redundant cluster interconnect connections to support your system configuration. For example, there are two redundant ports for a system with two dedicated cluster interconnect ports on each node.

Migrate the switches

About this task

The following procedure removes the cluster switches in a two-node cluster and replaces each connection to the switch with a direct connection to the partner node.

Cluster switches replaced with direct connections
About the examples

The examples in the following procedure show nodes that are using "e0a" and "e0b" as cluster ports. Your nodes might be using different cluster ports as they vary by system.

Step 1: Prepare for migration

  1. Change the privilege level to advanced, entering y when prompted to continue:

    set -privilege advanced

    The advanced prompt *> appears.

  2. ONTAP 9.3 and later supports automatic detection of switchless clusters, which is enabled by default.

    You can verify that detection of switchless clusters is enabled by running the advanced privilege command:

    network options detect-switchless-cluster show

    Show example

    The following example output shows if the option is enabled.

    cluster::*> network options detect-switchless-cluster show
   (network options detect-switchless-cluster show)
Enable Switchless Cluster Detection: true

    If "Enable Switchless Cluster Detection" is false, contact NetApp support.

  3. If AutoSupport is enabled on this cluster, suppress automatic case creation by invoking an AutoSupport message:

    system node autosupport invoke -node * -type all -message MAINT=<number_of_hours>h

    where h is the duration of the maintenance window in hours. The message notifies technical support of this maintenance task so that they can suppress automatic case creation during the maintenance window.

    In the following example, the command suppresses automatic case creation for two hours:

    Show example 
    cluster::*> system node autosupport invoke -node * -type all -message MAINT=2h

Step 2: Configure ports and cabling

  1. Organize the cluster ports on each switch into groups so that the cluster ports in group1 go to cluster switch1 and the cluster ports in group2 go to cluster switch2. These groups are required later in the procedure.

  2. Identify the cluster ports and verify link status and health:

    network port show -ipspace Cluster

    In the following example for nodes with cluster ports "e0a" and "e0b", one group is identified as “node1:e0a” and “node2:e0a” and the other group as “node1:e0b” and “node2:e0b”. Your nodes might be using different cluster ports because they vary by system.

    Cluster switch connections between node1 and node2

    Verify that the ports have a value of up for the “Link” column and a value of healthy for the “Health Status” column.

    Show example 
    cluster::> network port show -ipspace Cluster
Node: node1
                                                                 Ignore
                                             Speed(Mbps) Health  Health
Port  IPspace   Broadcast Domain Link  MTU   Admin/Oper	 Status  Status
----- --------- ---------------- ----- ----- ----------- ------- -------
e0a   Cluster   Cluster          up    9000  auto/10000  healthy false
e0b   Cluster   Cluster          up    9000  auto/10000  healthy false

Node: node2
                                                                 Ignore
                                             Speed(Mbps) Health  Health
Port  IPspace   Broadcast Domain Link  MTU   Admin/Oper	 Status  Status
----- --------- ---------------- ----- ----- ----------- ------- -------
e0a   Cluster   Cluster          up    9000  auto/10000  healthy false
e0b   Cluster   Cluster          up    9000  auto/10000  healthy false
4 entries were displayed.

  3. Confirm that all the cluster LIFs are on their home ports.

    Verify that the “is-home” column is true for each of the cluster LIFs:

    network interface show -vserver Cluster -fields is-home

    Show example 
    cluster::*> net int show -vserver Cluster -fields is-home
(network interface show)
vserver  lif          is-home
-------- ------------ --------
Cluster  node1_clus1  true
Cluster  node1_clus2  true
Cluster  node2_clus1  true
Cluster  node2_clus2  true
4 entries were displayed.

    If there are cluster LIFs that are not on their home ports, revert those LIFs to their home ports:

    network interface revert -vserver Cluster -lif *

  4. Disable auto-revert for the cluster LIFs:

    network interface modify -vserver Cluster -lif * -auto-revert false

  5. Verify that all ports listed in the previous step are connected to a network switch:

    network device-discovery show -port cluster_port

    The “Discovered Device” column should be the name of the cluster switch that the port is connected to.

    Show example

    The following example shows that cluster ports "e0a" and "e0b" are correctly connected to cluster switches "cs1" and "cs2".

    cluster::> network device-discovery show -port e0a|e0b
  (network device-discovery show)
Node/     Local  Discovered
Protocol  Port   Device (LLDP: ChassisID)  Interface  Platform
--------- ------ ------------------------- ---------- ----------
node1/cdp
          e0a    cs1                       0/11       BES-53248
          e0b    cs2                       0/12       BES-53248
node2/cdp
          e0a    cs1                       0/9        BES-53248
          e0b    cs2                       0/9        BES-53248
4 entries were displayed.

  6. Verify the connectivity of the remote cluster interfaces:

ONTAP 9.9.1 and later

You can use the network interface check cluster-connectivity command to start an accessibility check for cluster connectivity and then display the details:

network interface check cluster-connectivity start and network interface check cluster-connectivity show

cluster1::*> network interface check cluster-connectivity start

NOTE: Wait for a number of seconds before running the show command to display the details.

cluster1::*> network interface check cluster-connectivity show
                                  Source           Destination      Packet
Node   Date                       LIF              LIF              Loss
------ -------------------------- ---------------- ---------------- -----------
node1
       3/5/2022 19:21:18 -06:00   node1_clus2      node2-clus1      none
       3/5/2022 19:21:20 -06:00   node1_clus2      node2_clus2      none
node2
       3/5/2022 19:21:18 -06:00   node2_clus2      node1_clus1      none
       3/5/2022 19:21:20 -06:00   node2_clus2      node1_clus2      none
All ONTAP releases

For all ONTAP releases, you can also use the cluster ping-cluster -node <name> command to check the connectivity:

cluster ping-cluster -node <name>

cluster1::*> cluster ping-cluster -node local
Host is node2
Getting addresses from network interface table...
Cluster node1_clus1 169.254.209.69 node1 e0a
Cluster node1_clus2 169.254.49.125 node1 e0b
Cluster node2_clus1 169.254.47.194 node2 e0a
Cluster node2_clus2 169.254.19.183 node2 e0b
Local = 169.254.47.194 169.254.19.183
Remote = 169.254.209.69 169.254.49.125
Cluster Vserver Id = 4294967293
Ping status:

Basic connectivity succeeds on 4 path(s)
Basic connectivity fails on 0 path(s)

Detected 9000 byte MTU on 4 path(s):
Local 169.254.47.194 to Remote 169.254.209.69
Local 169.254.47.194 to Remote 169.254.49.125
Local 169.254.19.183 to Remote 169.254.209.69
Local 169.254.19.183 to Remote 169.254.49.125
Larger than PMTU communication succeeds on 4 path(s)
RPC status:
2 paths up, 0 paths down (tcp check)
2 paths up, 0 paths down (udp check)

  1. Verify that the cluster is healthy:

    cluster ring show

    All units must be either master or secondary.

  2. Set up the switchless configuration for the ports in group 1.

    Important To avoid potential networking issues, you must disconnect the ports from group1 and reconnect them back-to-back as quickly as possible, for example, in less than 20 seconds.

    1. Disconnect all the cables from the ports in group1 at the same time.

      In the following example, the cables are disconnected from port "e0a" on each node, and cluster traffic continues through the switch and port "e0b" on each node:

      ClusterSwitch1 disconnected

    2. Cable the ports in group1 back-to-back.

      In the following example, "e0a" on node1 is connected to "e0a" on node2:

      Direct connection between ports "e0a"

  3. The switchless cluster network option transitions from false to true. This might take up to 45 seconds. Confirm that the switchless option is set to true:

    network options switchless-cluster show

    The following example shows that the switchless cluster is enabled:

    cluster::*> network options switchless-cluster show
Enable Switchless Cluster: true

  4. Verify the connectivity of the remote cluster interfaces:

ONTAP 9.9.1 and later

You can use the network interface check cluster-connectivity command to start an accessibility check for cluster connectivity and then display the details:

network interface check cluster-connectivity start and network interface check cluster-connectivity show

cluster1::*> network interface check cluster-connectivity start

NOTE: Wait for a number of seconds before running the show command to display the details.

cluster1::*> network interface check cluster-connectivity show
                                  Source           Destination      Packet
Node   Date                       LIF              LIF              Loss
------ -------------------------- ---------------- ---------------- -----------
node1
       3/5/2022 19:21:18 -06:00   node1_clus2      node2-clus1      none
       3/5/2022 19:21:20 -06:00   node1_clus2      node2_clus2      none
node2
       3/5/2022 19:21:18 -06:00   node2_clus2      node1_clus1      none
       3/5/2022 19:21:20 -06:00   node2_clus2      node1_clus2      none
All ONTAP releases

For all ONTAP releases, you can also use the cluster ping-cluster -node <name> command to check the connectivity:

cluster ping-cluster -node <name>

cluster1::*> cluster ping-cluster -node local
Host is node2
Getting addresses from network interface table...
Cluster node1_clus1 169.254.209.69 node1 e0a
Cluster node1_clus2 169.254.49.125 node1 e0b
Cluster node2_clus1 169.254.47.194 node2 e0a
Cluster node2_clus2 169.254.19.183 node2 e0b
Local = 169.254.47.194 169.254.19.183
Remote = 169.254.209.69 169.254.49.125
Cluster Vserver Id = 4294967293
Ping status:

Basic connectivity succeeds on 4 path(s)
Basic connectivity fails on 0 path(s)

Detected 9000 byte MTU on 4 path(s):
Local 169.254.47.194 to Remote 169.254.209.69
Local 169.254.47.194 to Remote 169.254.49.125
Local 169.254.19.183 to Remote 169.254.209.69
Local 169.254.19.183 to Remote 169.254.49.125
Larger than PMTU communication succeeds on 4 path(s)
RPC status:
2 paths up, 0 paths down (tcp check)
2 paths up, 0 paths down (udp check)
Important Before proceeding to the next step, you must wait at least two minutes to confirm a working back-to-back connection on group 1.

  1. Set up the switchless configuration for the ports in group 2.

    Important To avoid potential networking issues, you must disconnect the ports from group2 and reconnect them back-to-back as quickly as possible, for example, in less than 20 seconds.

    1. Disconnect all the cables from the ports in group2 at the same time.

      In the following example, the cables are disconnected from port "e0b" on each node, and cluster traffic continues through the direct connection between the "e0a" ports:

      ClusterSwitch2 disconnected

    2. Cable the ports in group2 back-to-back.

      In the following example, "e0a" on node1 is connected to "e0a" on node2 and "e0b" on node1 is connected to "e0b" on node2:

      Direct connection between ports on node1 and node2

Step 3: Verify the configuration

  1. Verify that the ports on both nodes are correctly connected:

    network device-discovery show -port cluster_port

    Show example

    The following example shows that cluster ports "e0a" and "e0b" are correctly connected to the corresponding port on the cluster partner:

    cluster::> net device-discovery show -port e0a|e0b
  (network device-discovery show)
Node/      Local  Discovered
Protocol   Port   Device (LLDP: ChassisID)  Interface  Platform
---------- ------ ------------------------- ---------- ----------
node1/cdp
           e0a    node2                     e0a        AFF-A300
           e0b    node2                     e0b        AFF-A300
node1/lldp
           e0a    node2 (00:a0:98:da:16:44) e0a        -
           e0b    node2 (00:a0:98:da:16:44) e0b        -
node2/cdp
           e0a    node1                     e0a        AFF-A300
           e0b    node1                     e0b        AFF-A300
node2/lldp
           e0a    node1 (00:a0:98:da:87:49) e0a        -
           e0b    node1 (00:a0:98:da:87:49) e0b        -
8 entries were displayed.

  2. Re-enable auto-revert for the cluster LIFs:

    network interface modify -vserver Cluster -lif * -auto-revert true

  3. Verify that all LIFs are home. This might take a few seconds.

    network interface show -vserver Cluster -lif lif_name

    Show example

    The LIFs have been reverted if the “Is Home” column is true, as shown for node1_clus2 and node2_clus2 in the following example:

    cluster::> network interface show -vserver Cluster -fields curr-port,is-home
vserver  lif           curr-port is-home
-------- ------------- --------- -------
Cluster  node1_clus1   e0a       true
Cluster  node1_clus2   e0b       true
Cluster  node2_clus1   e0a       true
Cluster  node2_clus2   e0b       true
4 entries were displayed.

    If any cluster LIFS have not returned to their home ports, revert them manually from the local node:

    network interface revert -vserver Cluster -lif lif_name

  4. Check the cluster status of the nodes from the system console of either node:

    cluster show

    Show example

    The following example shows epsilon on both nodes to be false:

    Node  Health  Eligibility Epsilon
----- ------- ----------- --------
node1 true    true        false
node2 true    true        false
2 entries were displayed.

  5. Verify the connectivity of the remote cluster interfaces:

ONTAP 9.9.1 and later

You can use the network interface check cluster-connectivity command to start an accessibility check for cluster connectivity and then display the details:

network interface check cluster-connectivity start and network interface check cluster-connectivity show

cluster1::*> network interface check cluster-connectivity start

NOTE: Wait for a number of seconds before running the show command to display the details.

cluster1::*> network interface check cluster-connectivity show
                                  Source           Destination      Packet
Node   Date                       LIF              LIF              Loss
------ -------------------------- ---------------- ---------------- -----------
node1
       3/5/2022 19:21:18 -06:00   node1_clus2      node2-clus1      none
       3/5/2022 19:21:20 -06:00   node1_clus2      node2_clus2      none
node2
       3/5/2022 19:21:18 -06:00   node2_clus2      node1_clus1      none
       3/5/2022 19:21:20 -06:00   node2_clus2      node1_clus2      none
All ONTAP releases

For all ONTAP releases, you can also use the cluster ping-cluster -node <name> command to check the connectivity:

cluster ping-cluster -node <name>

cluster1::*> cluster ping-cluster -node local
Host is node2
Getting addresses from network interface table...
Cluster node1_clus1 169.254.209.69 node1 e0a
Cluster node1_clus2 169.254.49.125 node1 e0b
Cluster node2_clus1 169.254.47.194 node2 e0a
Cluster node2_clus2 169.254.19.183 node2 e0b
Local = 169.254.47.194 169.254.19.183
Remote = 169.254.209.69 169.254.49.125
Cluster Vserver Id = 4294967293
Ping status:

Basic connectivity succeeds on 4 path(s)
Basic connectivity fails on 0 path(s)

Detected 9000 byte MTU on 4 path(s):
Local 169.254.47.194 to Remote 169.254.209.69
Local 169.254.47.194 to Remote 169.254.49.125
Local 169.254.19.183 to Remote 169.254.209.69
Local 169.254.19.183 to Remote 169.254.49.125
Larger than PMTU communication succeeds on 4 path(s)
RPC status:
2 paths up, 0 paths down (tcp check)
2 paths up, 0 paths down (udp check)

  1. If you suppressed automatic case creation, reenable it by invoking an AutoSupport message:

    system node autosupport invoke -node * -type all -message MAINT=END

    For more information, see NetApp KB Article 1010449: How to suppress automatic case creation during scheduled maintenance windows.

  2. Change the privilege level back to admin:

    set -privilege admin