Andreas Rammhold 55c09a884a nixos/modules/system/boot/networkd: enable socket activation ... Since cd1dedac67 systemd-networkd has it's netlink socket created via a systemd.socket unit. One might think that this doesn't make much sense since networkd is just going to create it's own socket on startup anyway. The difference here is that we have configuration-time control over things like socket buffer sizes vs compile-time constants. For larger setups where networkd has to create a lot of (virtual) devices the default buffer size of currently 128MB is not enough. A good example is a machine with >100 virtual interfaces (e.g., wireguard tunnels, VLANs, …) that all have to be brought up during startup. The receive buffer size will spike due to all the generated message from the new interfaces. Eventually some of the message will be dropped since there is not enough (permitted) buffer space available. By having networkd start through / with a netlink socket created by systemd we can configure the `ReceiveBufferSize` parameter in the socket options without recompiling networkd. Since the actual memory requirements depend on hardware, timing, exact configurations etc. it isn't currently possible to infer a good default from within the NixOS module system. Administrators are advised to monitor the logs of systemd-networkd for `rtnl: kernel receive buffer overrun` spam and increase the memory as required. Note: Increasing the ReceiveBufferSize doesn't allocate any memory. It just increases the upper bound on the kernel side. The memory allocation depends on the amount of messages that are queued on the kernel side of the netlink socket.		2020-06-16 00:41:41 +02:00
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manual	nixos/modules/system/boot/networkd: enable socket activation	2020-06-16 00:41:41 +02:00
varlistentry-fixer.rb
xmlformat.conf	doc: Disable wrapping source	2019-09-18 21:17:52 +02:00