New Jun 13, 2025

Learn about FSx for ONTAP FlexCache Write-back

The Giants All from DEV Community View Learn about FSx for ONTAP FlexCache Write-back on dev.to

Today I’ll introduce a new feature of Amazon FSx for NetApp ONTAP, the Writeback mode of ONTAP FlexCache.
AWS What's new
This feature was originally offered in ONTAP version 9.15.1 and later and is now available on AWS at no cost.

About ONTAP FlexCache

ONTAP FlexCache is a mechanism that temporarily stores data from the original volume (origin volume) in a cache volume in a different location so that users can access the data from that cache at high speed.
Protocols are available for both SMB (Windows) / NFS (Linux).

  1. Faster Reads
    By caching frequently accessed data locally, read performance is greatly improved.

  2. Bandwidth savings
    Reduces access across the WAN, minimizing network bandwidth usage.

  3. Distributed access
    Even when the same data is accessed at multiple locations, caches can be placed at each location.

  4. Automatic Synchronization
    Changes to the origin volume are reflected in the cache as needed.

  5. Read-only or read/write support
    FlexCache is basically read-only, but can also be written under certain conditions.

Use Case #1

Utilize data in the cloud with on-premise as the origin
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Use Case #2

On-premises caching of cloud file servers

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This configuration is useful when the access speed from on-premises to the cloud is not fast enough.

Use Case #3

Data collaboration and aggregation between locations
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Detailed in FlexCache WriteBack

Write-back mode is a new ONTAP capability that helps you achieve faster performance for your write-intensive workloads that are distributed across multiple AWS Regions and on-premises file systems.

Write-back from cache to origin happens asynchronously. This means that dirty data isn't immediately written back to the origin.

FlexCache write-back involves many complex interactions between the origin and caches. For optimal performance, you should ensure your environment follows some requirements or guides that NetApp provides based on official document.

When is this effective?

Distributed file systems can be realized.
It's possible to improve performance at near-local speeds for specific workloads and environments, resulting in significant performance benefits, as for the case of content creation, distributed databases, and engineering workflows that need to operate across multiple AWS Regions or between cloud and on-premises environments.

ONTAP FlexCache write-back prerequisites

The origin must be running ONTAP 9.15.1 or later.
Please check the latest document

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