[Pdns-users] Recursor Cache Sizing: Is more always better?

Winfried walists at mailbox.org
Sat Sep 9 07:59:19 UTC 2023

Hi Christoph,

My recommendation is to limit the TTL to 12 or 6 hours and find out how many cache entries are created during this time. Increase that by 50% and that's your value. You'll see that it doesn't require that much memory space.


Am 9. September 2023 09:15:04 MESZ schrieb Christoph via Pdns-users <pdns-users at mailman.powerdns.com>:
>if you have 20 or 100 GB of free RAM
>what is a good approach to choose the different Recursor's cache sizes?
>Is larger always better or is there a sweet spot
>between cache size, cache lookup time, cache management overhead and CPU usage? How does upstream latency fit into the equation?
>In our case we consider caching and prefetching also an important privacy property to decouple inbound and outbound queries to some extend.
>We have different kinds of setups:
>- fully recursive resolvers
>- forwarding resolvers (~12ms upstream latency)
>best regards,
>Pdns-users mailing list
>Pdns-users at mailman.powerdns.com

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