Value of linux net.ipv6.route.max_size

[Willy Manga <willym () manbene net>]

Hi,

I recently noticed an issue with some routers complaining with that message:

"kernel: Route cache is full: consider increasing sysctl 
net.ipv6.route.max_size."

These routers are running FRR on Debian 12 , kernel 6.1.0-17-amd64. They 
are receiving full routing table and routes are inserted into the kernel 
routing table.

I saw a similar error here [1] and it leads me to [2] as well but I 
should admit I did not read everything.

I did not dive into the details of the two links but for now , I want to 
increase that value (and find the source of that error).

The current value of net.ipv6.route.max_size is: 4096 . I guess it's the 
default on at least that kernel.

For reference net.ipv4.route.max_size=2147483647 .

Of course, we cannot correlate the two but I was wondering, what either 
people are using or what might be a reasonable value for the IPv6 
counterpart.


1. https://bugzilla.redhat.com/show_bug.cgi?id=1813691

2. 
https://lore.kernel.org/netdev/e022d597-302d-c061-0830-6ed20aa61e56 () qtmlabs xyz/T/#u

--
Willy Manga