The NetApp® ONTAP® six-month release cadence was designed to bring new features in rapid succession, and ONTAP 9.3 does not disappoint.


Prior to ONTAP 9.3, the list of supported features for NetApp FlexGroup volumes looked like this:

Table 1) Supported ONTAP Features with NetApp FlexGroup volumes.

The New Stuff

What’s new in ONTAP 9.3 for FlexGroup volumes? I’m glad you asked.

Improved Home Directory Support

NetApp FlexGroup volumes provide a large, scalable NAS container that can span multiple nodes and grow to massive capacity nondisruptively, while providing a single namespace. That sort of container is a great fit for home directory workloads.


Prior to ONTAP 9.3, some features that are critical to home directory workloads were not available. ONTAP 9.3 brings us closer to FlexGroup volumes being a perfect fit for home directories, with support added for qtrees, SMB change/notify, antivirus scanning, and quality of service (QoS) maximums.


Many customers use qtrees for home directory folders for users for several reasons:

  • They’re easy. You can manage them from the storage system, automate home folder creation easily, and apply dynamic homedir shares for multiprotocol SMB and NFS access.
  • They’re flexible. You can apply individual export policy rules to limit access from the storage.
  • They’re granular. Qtrees provide a logical separation of data inside a volume, which is particularly useful in a large container such as a FlexGroup volume. You can apply quotas to qtrees to manage space allocation. Currently, FlexGroup supports only quota monitoring. Stay tuned for quota enforcement in future releases.

SMB Change/Notify

SMB change/notify allows clients to write data to shares and see that data immediately after writing it, without having to intervene by refreshing the window or closing and reopening the connection. This is especially useful in workloads with applications that must read files right after they are written.

Antivirus Scanning

FlexGroup volumes provide support for off-box antivirus scanning, which is crucial in home directory workloads. Antivirus in a FlexGroup volume works just like in a FlexVol® volume. Support is currently being qualified for ONTAP FlexGroup volumes with the following major antivirus scanning software vendors:

  • Kaspersky
  • McAfee
  • Sophos
  • Symantec
  • Trend Micro

QoS Maximums

In a home directory workload, you don’t want users stepping on production workloads, so you can apply QoS maximums to your FlexGroup volumes to limit the MBps and IOPS being used by the volume. QoS maximums are applied at the FlexGroup or storage virtual machine (SVM) level. Currently, only the command line is supported. At a high level, QoS maximums are shared across nodes where the FlexGroup volume lives. (See Figure 1.)

Figure 1) Quality of Service Maximum – NetApp FlexGroup volume example.

Improved Data Protection Support

FlexGroup volumes in ONTAP 9.3 also offer better support for data protection with the following feature additions:

Unified Replication and Version-Independent SnapMirror

ONTAP 9.3 introduces support for unified replication on FlexGroup volumes. This means that FlexGroup volumes will use the XDP replication engine by default, which allows SnapMirror® and SnapVault®, as well as version-independent SnapMirror. Version independence is when you can replicate between two different ONTAP versions (within two releases) with no issues. Previous versions of ONTAP required the destination to be on the same or a later release as the source to make sure of the ability to fail over in DR scenarios.


FlexGroup volumes also now support SnapVault, which means you can keep more Snapshot™ copies on a destination than on the source, for archival purposes. This is one way you can adequately back up a FlexGroup volume quickly by replicating to a DR site. From there, you can point protocol-based backups to the SnapVault destination and offload the jobs from the production system. (See Figure 2.)


Figure 2) SnapMirror and SnapVault differences – NetApp FlexGroup volume.

FlexGroup Expansion Without Needing to Rebaseline

FlexGroup volumes can have their size increased in one of two ways: by growing the member volumes or by adding new member volumes. Adding new member volumes is known as “FlexGroup expansion.” This increases the member volume count, which, in previous ONTAP releases, would force you to rebaseline SnapMirror relationships. In ONTAP 9.3, the expansion of a FlexGroup volume no longer requires a lengthy rebaseline of the relationship.

Improved FlexGroup Space Management

A NetApp FlexGroup volume is built with multiple FlexVol members. These FlexVol members are all limited to a finite amount of capacity and inode counts. When a FlexGroup member volume runs out of space or inodes, the entire FlexGroup volume reports as being out of space or inodes, even if other member volumes have available space. While this scenario is rare, it still requires consideration. In ONTAP 9.3, a few improvements have been made to help avoid such scenarios.

Volume Autogrow

If a FlexGroup member volume runs out of space, the entire FlexGroup volume is considered out of space until the issue is remedied. That situation required administrator intervention until ONTAP 9.3 and volume autogrow.


Volume autogrow can get your FlexGroup volume out of sticky situations by growing the volume to avoid “out of space” errors.

Improved Ingest Heuristics

“Ingest heuristics” refers to the way ONTAP processes the balancing of file ingest into a FlexGroup volume. In addition to capacity, member volumes can run out of inodes, which creates an issue similar to what you’d see with an “out of space” error. Previous ONTAP versions did not factor in a member volume’s inode count. ONTAP 9.3 does. As a member volume approaches its maximum capacity and inode count, ONTAP avoids that volume until the other volumes have caught up.


There you have it. ONTAP 9.3 is bringing even more feature functionality to FlexGroup volumes. This time it is better enabling home directory workloads, providing more robust data protection, and improving the space management of a FlexGroup volume on ingest of files.

Get More Information

In Announcing NetApp ONTAP 9.3: The Next Step in Modernizing Your Data Management, Jeff Baxter covers how ONTAP 9.3 is modernizing your data center with the new features it brings.


I cover FlexGroup volumes in general in NetApp FlexGroup Volumes: An Evolution of NAS, as well as in this short video:



I also go into detail about FlexGroup volumes and best practices in the following technical reports:

Justin Parisi

Justin Parisi is an ONTAP veteran, with over 10 years of experience at NetApp. He is co-host of the NetApp Tech ONTAP Podcast, Technical Advisor with the NetApp A-Team and works as a Technical Marketing Engineer at NetApp, focusing on FlexGroup volumes and all things NAS-related.

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