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Increase default gc_thresh
Open, Requires assessmentPublicFEATURE REQUEST


By default sysctl params for gc_thresh is small if we use VyOS as BRAS or DHCP Server (L2).
Also it can take negative effect if we use VRRP and active arp entries more than 512.
Default params:

net.ipv4.neigh.default.gc_thresh1 = 128
net.ipv4.neigh.default.gc_thresh2 = 512
net.ipv4.neigh.default.gc_thresh3 = 1024

net.ipv6.neigh.default.gc_thresh1 = 128
net.ipv6.neigh.default.gc_thresh2 = 512
net.ipv6.neigh.default.gc_thresh3 = 1024

Proposed params:

net.ipv4.neigh.default.gc_thresh1 = 2048
net.ipv4.neigh.default.gc_thresh2 = 4096
net.ipv4.neigh.default.gc_thresh3 = 8192

net.ipv6.neigh.default.gc_thresh1 = 2048
net.ipv6.neigh.default.gc_thresh2 = 4096
net.ipv6.neigh.default.gc_thresh3 = 8192

Sure we can increase this params via CLI, but I think best practices if we add this params by default.

set system ip arp table-size 8192
set system ipv6 neighbor table-size 8192


Difficulty level
Unknown (require assessment)
Why the issue appeared?
Will be filled on close
Is it a breaking change?
Perfectly compatible

Event Timeline

Dmitry created this task.Tue, Nov 26, 10:35 PM
pasik added a subscriber: pasik.Wed, Nov 27, 6:19 PM