Logical availability zones (LAZ) provide multiple logical grouping of nodes and distribute the data across these groups in such a way that no single group has more than one copy of the data. This enables enhanced protection from node failures, allowing for more nodes to fail while the overall cluster remains online. After you have successfully configured your HyperFlex cluster, refer to the commands in Table 15-4 to enable or disable logical availability zones.

Table 15-4 LAZ Enable and Disable stcli Commands

Note

Wait for at least 10 seconds between successive invocations of LAZ disable and LAZ enable operations in that order.

In case of a fresh cluster installation, for best results, it is recommended that LAZ is enabled during cluster creation.

There are several requirements and guidelines for configuring logical availability zones in a cluster. If you choose to ignore these requirements, you can expand the cluster with the following procedure:

Step 1. Disable LAZ:

stcli cluster –set-zone 0

You must wait for a few minutes—roughly around five minutes—for LAZ to be disabled.

Step 2. Add nodes to the cluster.

Step 3. After the nodes are added to the cluster, enable LAZ:

stcli cluster set-zone –zone 1

If the number of zones is not set explicitly, by default, four zones are created.

Step 4. Initiate rebalancing in the cluster:

stcli rebalance start

Note

Rebalancing nodes may decrease the performance of the cluster by about 30 to 40 percent. The time taken to rebalance the nodes in the cluster depends on the cluster size and the data within the cluster. You can use the stcli rebalance status command to review the progress of the rebalancing activity.

Step 5. Review the cluster configuration and determine if the cluster is zone compliant:

stcli cluster –get-zone