If your vSAN cluster is out of storage capacity or when you notice reduced performance, you can expand the cluster for capacity and performance.
- (Only for vSAN Original Storage Architecture) Expand the storage capacity of your cluster either by adding storage devices to existing disk groups or by adding disk groups. New disk groups require flash devices for the cache. For information about adding devices to disk groups, see Add Devices to the Disk Group in vSAN Cluster. Adding capacity devices without increasing the cache might reduce your cache-to-capacity ratio to an unsupported level. For more information See vSAN Planning and Deployment
Improve the cluster performance by adding at least one cache device (flash) and one capacity device (flash or magnetic disk) to an existing storage I/O controller or to a new host. Or you can add one or more hosts with disk groups to produce the same performance impact after vSAN completes automatic rebalance in the vSAN cluster.
- (Only for vSAN Express Storage Architecture) Expand the storage capacity of your cluster by adding flash devices to the storage pools of the existing hosts or by adding one or more new hosts with flash devices.
Although compute-only hosts can exist in a vSAN cluster, and consume capacity from other hosts in the cluster, add uniformly configured hosts for efficient operation. Although it is best to use the same or similar devices in your disk groups or storage pools, any device listed on the vSAN HCL is supported. Try to distribute capacity evenly across hosts. For information about adding devices to disk groups or storage pools, see Create a Disk Group or Storage Pool in vSAN Cluster.
After you expand the cluster capacity, enable automatic rebalance to distribute resources evenly across the cluster. For more information, see vSAN Monitoring and Troubleshooting.
