In an HCI cluster, expanding storage by adding drives on the available slots on the cluster nodes adds storage capacity to the cluster and improves storage performance. Before the storage expansion, ensure that all disk types and the amount in each node are the same and are equal to that of the node in use. Do not combine two different disk types in the same cluster or node. For example, you cannot combine SATA and SAS HDD/SSD drives in the same node or cluster.
The following options for expanding the storage capacity of the cluster are supported:
- Option 1: Expand the storage with the same drive manufacturer, capacity, endurance, latest model, and latest firmware. Determine if it is available on the AX node support matrix.
- Option 2: Expand the storage with a different drive manufacturer, model, firmware, and the same capacity and endurance. Determine if it is available on the AX node support matrix.
When new disks are added to extend the overall storage capacity per node, the Azure Stack HCI cluster starts claiming the physical disks into an existing storage pool.
After the drives are added, they are shown as available for pooling (CanPool set to True) in the output of the Get-PhysicalDisk command.
Within a few minutes, the newly added disks are claimed in the existing pool and Storage Spaces Direct starts the rebalance job. Run the following command to verify that the new disks are a part of the existing pool:
PS C:\> Get-ClusterPerformanceHistory -FriendlyName *Cluster* | Get-StorageHealthReport
CPUUsageAverage : 2.66 %
CapacityPhysicalPooledAvailable : 8.01 TB
CapacityPhysicalPooledTotal : 69.86 TB
CapacityPhysicalTotal : 69.86 TB
CapacityPhysicalUnpooled : 0 B
CapacityVolumesAvailable : 15.09 TB
CapacityVolumesTotal : 16.88 TB
IOLatencyAverage : 908.13 us
IOLatencyRead : 0 ns
IOLatencyWrite : 908.13 us
IOPSRead : 0 /S
IOPSTotal : 1 /S
IOPSWrite : 1 /S
IOThroughputRead : 0 B/S
IOThroughputTotal : 11.98 KB/S
IOThroughputWrite : 11.98 KB/S
MemoryAvailable : 472.87 GB
MemoryTotal : 768 GB
After all available disks are claimed in the storage pool, the CapacityPhysicalUnpooled is 0 B.
The storage rebalance job might take a few minutes. You can monitor the process by using the Get-StorageJob cmdlet.