❦ 21 janvier 2020 18:58 +00, Tim Bray <tim@provu.co.uk>:
> I also agree.
>
> I've just spent a month tracking down an issue where IPv6 networking
> connections hang. Using Debian buster, 4.19.0-6-amd64.
>
> Machine carries a full IPv6 table, received via BGP. About 80k routes.
>
> Symptoms were BFD dropping out. Connectivity hangs.
>
> setting net.ipv6.route.max_size to 2147483647 fixed all issues.
> (aware this might be too big)
>
> Later kernels (5.4.11) cause a dmesg when full.
This setting is for the size of the route cache. You can have far more
routes. In the past, there were bugs where each lookup will be put in
cache, but since 4.2, only the PMTU exceptions are stored in cache. See
<https://vincent.bernat.ch/en/blog/2017-ipv6-route-lookup-linux#caching>
Do you have a lot of entries in `ip -6 route show cache`?
--
Avoid multiple exits from loops.
- The Elements of Programming Style (Kernighan & Plauger)
Attachment:
signature.asc
Description: PGP signature