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ONTAP FlexCache write-back prerequisites

Contributors netapp-dbagwell elliott-ecton
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Before you deploy FlexCache in write-back mode, ensure you have met these performance, software, licensing, and system configuration requirements.

CPU and Memory

Each origin cluster node should have at least 128GB of RAM and 20 CPUs to absorb the write-back messages initiated by write-back enabled caches. This is the equivalent of an A400 or greater. If the origin cluster serves as the origin to multiple write-back enabled FlexCaches, it will require more CPU and RAM.

Caution Using an undersized origin for your workload can have profound impacts on performance at the write-back-enabled cache or the origin.

ONTAP version

  • The origin must be running ONTAP 9.15.1 or later.

  • Any caching cluster that needs to operate in write-back mode must be running ONTAP 9.15.1 or later.

  • Any caching cluster that does not need to operate in write-back mode can run any generally supported ONTAP version.

Licensing

FlexCache, including the write-back mode of operation, is included with your ONTAP purchase. No extra license is required.

Peering

  • The origin and cache clusters must be cluster peered

  • The server virtual machines (SVMs) on the origin and cache cluster must be vserver peered with the FlexCache option.

Note You do not need to peer a cache cluster to another cache cluster. There is also no need to peer a cache SVM to another cache SVM.