Expanding cluster compute or storage capacity are tasks performed during cluster operations. This section provides instructions for performing these tasks.
In an HCI cluster, adding server nodes increases the storage capacity, improves the overall storage performance of the cluster, and provides more compute resources to add virtual machines. Before adding new server nodes to an HCI cluster, complete the following requirements:
Option 1 conditions
Option 2 conditions
Ensure that the following tasks are completed:
To manually add server nodes to the cluster, see https://technet.microsoft.com/windows-server-docs/storage/storage-spaces/add-nodes.
In an HCI cluster, expanding storage by adding drives on the available slots on the cluster nodes adds storage capacity of the cluster and improves storage performance. Before the storage expansion, ensure that all disk types and the amount in each node is 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 same node or cluster.
The following options for expanding the storage capacity of the cluster are supported:
When new disks are added to extend the overall storage capacity per node, the Storage Spaces Direct 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-StorageSubSystem -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.