BR_PORT_BITS - limit of bridges

[Alibek]

Hi!

Linux kernel have default hardcoded parameter BR_PORT_BITS = 10. This param limit max bridges to 1024 (2^10 = 1024).
In some cases need increase this param - for example qty containers over 1024 - big lxc containers with nested dockers containers.

I know BR_PORT_BITS limit is inspired by limitation of STP protocol, but i think this limit not is valid for current real cases (for example I use 'bridge_stp off' on all pve-hosts, and STP control is assigned to the switches).
Moving on openvswitch doesn't solve problem with dockers in lxc.

I think the limit of BR_PORTS_BITS needs replace from hardcoded to manage by sysctl
Proxmox team, how about made this in pve-kernels?

 

[spirit]

Hi, not sure you can replace it easily with a sysctl.
but it could be bumped to 14 (16000)

also, it's possible to workaround it with multiple bridges on top of a single bridge (and latency is also better with more bridges)
http://events17.linuxfoundation.org/sites/events/files/slides/Scaling_1.pdf

 

[Alibek]

@proxmox-kernel-team can you be increase this limit in pve-kernel by default?

 

[Alibek]

up

 

[Alibek]

Please increase BR_PORT_BITS in pve kernel. It is must have with Nested containers.