topic Re: Trying to understand caching policy in ONTAP Discussions

Trying to understand caching policy

Rud — Wed, 04 Jun 2025 09:53:03 GMT

So I am trying understand the caching policy settings.

I found them here: https://docs.netapp.com/us-en/active-iq-unified-manager-99/online-help/reference-volume-health-fields.html

There are lines that I do not understand, for example: "This policy is a combination of the Meta and No Read-Random Write and does the following: Read caches only"... but Meta caches only metadata and no-read-random write does not cache writes for reads?

Or perhaps I am misunderstanding, "Write cache random overwritten user data", I write caching to tier 1 of random data

written.

It is like one of those puzzles in the back of the newspaper so I tried to put it into a spreadsheet so it is quicker to understand than the documentation. IDK if I have understood I correctly, but I think it would be easier to understand than the long list that looks like it has been reverse engineered from the software. 😄

Are there anyone who can look at the spreadsheet.png and see if I have understood it correctly? 😄

Re: Trying to understand caching policy

paul_stejskal — Tue, 07 Feb 2023 15:15:01 GMT

Compare it with https://kb.netapp.com/Advice_and_Troubleshooting/Data_Storage_Systems/FAS_Systems/How_to_modify_caching_policies_of_Flash_Pool_aggregate and see if this helps explain it. If it's clearer we can request the documentation be updated. Good find. It's a complicated subject and we are definitely open for tips to make the KB and docs clearer.

Re: Trying to understand caching policy

Rud — Wed, 08 Feb 2023 10:01:20 GMT

Hi,

Thanks for the link, I had not found that one, that is a good explanation.

Do you know if this is covered in the "ONTAP Performance Analysis" training or one of the other modules?

Re: Trying to understand caching policy

paul_stejskal — Wed, 08 Feb 2023 18:11:11 GMT

Sorry no idea.