Skip to main content

Determine the number of disks or disk partitions required for a local tier in ONTAP

Contributors netapp-thomi netapp-ahibbard netapp-lenida netapp-revathid netapp-aherbin

You must have enough disks or disk partitions in your local tier to meet system and business requirements. You should also have the recommended number of hot spare disks or hot spare disk partitions to minimize the potential of data loss.

Root-data partitioning is enabled by default on certain configurations. Systems with root-data partitioning enabled use disk partitions to create local tiers. Systems that do not have root-data partitioning enabled use unpartitioned disks.

You must have enough disks or disk partitions to meet the minimum number required for your RAID policy and enough to meet your minimum capacity requirements.

Note

In ONTAP, the usable space of the drive is less than the physical capacity of the drive. You can find the usable space of a specific drive and the minimum number of disks or disk partitions required for each RAID policy in the Hardware Universe.

Determine usable space of a specific disk

The procedure you follow depends on the interface you use—​System Manager or the CLI:

Use System Manager to determine usable space of disks

Perform the following steps to view the usable size of a disk:

Steps
  1. Go to Storage > Tiers

  2. Click Menu options icon next to the name of the local tier.

  3. Select the Disk Information tab.

In addition to the number of disks or disk partitions necessary to create your RAID group and meet your capacity requirements, you should also have the minimum number of hot spare disks or hot spare disk partitions recommended for your local tier:

  • For all flash local tiers, you should have a minimum of one hot spare disk or disk partition.

    Note

    The AFF C190 defaults to no spare drive. This exception is fully supported.

  • For non-flash homogenous local tiers, you should have a minimum of two hot spare disks or disk partitions.

  • For SSD storage pools, you should have a minimum of one hot spare disk for each HA pair.

  • For Flash Pool local tiers, you should have a minimum of two spare disks for each HA pair. You can find more information on the supported RAID policies for Flash Pool local tiers in the Hardware Universe.

  • To support the use of the Maintenance Center and to avoid issues caused by multiple concurrent disk failures, you should have a minimum of four hot spares in multi-disk carriers.

Related information

NetApp Hardware Universe