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ONTAP FlexCache Write-back interoperability

Contributors netapp-dbagwell elliottecton
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Understand these interoperability considerations when deploying FlexCache in write-back mode.

ONTAP version

To use the write-back mode of operation, both the cache and origin must be running ONTAP 9.15.1 or later.

Note Clusters where a write-back-enabled cache is unnecessary can run earlier versions of ONTAP, but that cluster can only operate in write-around mode.

You can have a mix of ONTAP versions in your environment.

Table 1. Mixed cluster versions example 1
Cluster ONTAP version Write-back supported?

Origin

ONTAP 9.15.1

N/A †

Cluster 1

ONTAP 9.15.1

Yes

Cluster 2

ONTAP 9.14.1

No
Table 2. Mixed cluster versions example 2
Cluster ONTAP version Write-back supported?

Origin

ONTAP 9.14.1

N/A †

Cluster 1

ONTAP 9.15.1

No

Cluster 2

ONTAP 9.15.1

No

† Origins aren't a cache, so neither write-back nor write-around support is applicable.

Note In Mixed cluster versions example 2, neither cluster can enable write-back mode because the origin is not running ONTAP 9.15.1 or later, which is a strict requirement.

Client interoperability

Any client generally supported by ONTAP can access a FlexCache volume regardless of whether it is operating in write-around or write-back mode. For an up-to-date list of supported clients, refer to NetApp's interoperability matrix.

Although the client version doesn't matter specifically, the client must be new enough to support NFSv3, NFSv4.0, NFSv4.1, SMB2.x, or SMB3.x. SMB1 and NFSv2 are deprecated protocols and are not supported.

Write-back and write-around

As seen in Mixed cluster versions example 1, FlexCache operating in write-back mode can co-exist with caches operating in write-around mode. It is advised to compare write-around against write-back with your specific workload.

Tip If the performance for a workload is the same between write-back and write-around, use write-around.

ONTAP feature interoperability

For the most up-to-date list of FlexCache feature interoperability, refer to the supported and unsupported features for FlexCache volumes.