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NetApp RAID Configuration (ONTAP): Choosing the Right Level for Your Storage

  • Writer: server-parts.eu server-parts.eu
    server-parts.eu server-parts.eu
  • Dec 1, 2024
  • 3 min read

Updated: Nov 1

In NetApp ONTAP, RAID protection is part of the local-tier (aggregate) design. ONTAP offers RAID-DP and RAID-TEC to protect against multiple, simultaneous disk failures without significant performance loss.


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Picking the right protection level and RAID group size keeps usable capacity, protection, and rebuild risk balanced.


NetApp ONTAP RAID-DP and RAID-TEC storage configuration for enterprise data protection. Server-parts.eu. used. refurbished.


RAID options in NetApp ONTAP


NetApp RAID4

  • Single parity.

  • Protects from one disk failure in a RAID group.

  • Considered legacy.


NetApp RAID-DP (double parity)

  • Survives two simultaneous disk failures in the same RAID group.

  • Parity calculations occur in memory, minimizing write penalties.

  • Suitable for most mixed or transactional workloads.

  • Can be converted from RAID-TEC when triple parity is no longer needed.


NetApp RAID-TEC (triple erasure coding)

  • Survives three simultaneous disk failures in a RAID group.

  • Designed for large-capacity media with long rebuild times.

  • ONTAP uses it automatically for capacity HDD tiers (6 TB or larger).

  • Works on all disk types, including SSDs, and supports large RAID groups.



When to use each NetApp ONTAP (RAID)


NetApp RAID-DP: Use it for databases, virtual machines, and general-purpose NAS or SAN workloads. It offers a good balance between efficiency and fault tolerance.


NetApp RAID-TEC: Use it for high-capacity HDD tiers where rebuilds take longer and the probability of multiple failures is higher. It is standard for data-intensive capacity tiers, archival systems, and large FlexGroup environments.



RAID group sizing - NetApp ONTAP


NetApp guidance:


  • NetApp HDD or array-LUN RAID groups: 12–20 disks recommended. Up to 28 disks possible on high-performance drives.


  • NetApp SSD RAID-DP groups: 20–28 disks recommended.All RAID groups in the same aggregate should have similar sizes. Larger groups provide higher usable capacity but increase the time a system runs in a degraded state.



Creating aggregates RAID in NetApp ONTAP (CLI)


NetApp RAID-DP example:

storage aggregate create -aggregate aggr_data01 -node node1 -diskcount 20 -raidtype raid_dp

NetApp RAID-TEC example:

storage aggregate create -aggregate aggr_cap01 -node node1 -diskcount 20 -raidtype raid_tec

ONTAP can automatically select disks from spare pools or you can define a specific disk list. You can also specify maximum RAID group size when creating the aggregate.



Monitoring and replacing failed disks (RAID) - NetApp ONTAP


Check aggregate and RAID status:

storage aggregate show
storage aggregate show-status -aggregate <name>

Find failed disks:

storage disk show -state broken

Assign a replacement disk (only when auto-assignment is disabled):

storage disk assign -disk <disk_name> -pool 0

Select the correct pool (0 or 1) according to your MetroCluster or SyncMirror setup.Active IQ Unified Manager or Digital Advisor can provide early alerts before a RAID group becomes at risk.



Rebuild time considerations (RAID) - NetApp ONTAP


Larger disks and larger RAID groups increase rebuild time. RAID-TEC reduces the risk of a second or third failure during rebuild by adding extra parity protection. Exact rebuild duration depends on disk capacity, workload, and controller load.



Converting RAID-TEC to RAID-DP - NetApp ONTAP


If a capacity tier shrinks or triple parity is unnecessary, you can convert:

storage aggregate modify -aggregate <name> -raidtype raid_dp

Verify status:

storage aggregate show <name>

Conversion is allowed only when the RAID group meets RAID-DP limits.



NetApp Storage & Parts: Save Up To 80%

✔️ 5-Year Warranty – No Risk: Pay Only After Testing



Sources - NetApp ONTAP


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