From ca32f89fb27152fc477d812e95f9a1485cb75f7b Mon Sep 17 00:00:00 2001 From: bugclerk <40872210+bugclerk@users.noreply.github.com> Date: Mon, 5 Aug 2024 14:43:54 -0400 Subject: [PATCH] drop ntb0 MTU to 64000 (#14137) (cherry picked from commit 4c97bdd827ef011d1cdba52bae93593ebde3a9a5) Co-authored-by: caleb --- src/freenas/etc/systemd/network/10-persistent-net.link | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/src/freenas/etc/systemd/network/10-persistent-net.link b/src/freenas/etc/systemd/network/10-persistent-net.link index 1abd9b3ed3662..d79f2554adcd8 100644 --- a/src/freenas/etc/systemd/network/10-persistent-net.link +++ b/src/freenas/etc/systemd/network/10-persistent-net.link @@ -1,5 +1,15 @@ [Match] Driver=ntb_netdev + [Link] Name=ntb0 +# TODO: at time of writing, ntb on SCALE has pathological +# behavior related TCP/IP Window size calculation whereby +# the receiving side clamps the window size to 0 causing +# recalculation which, ultimately, ends with behavior +# described in https://en.wikipedia.org/wiki/Silly_window_syndrome +# The work-around is to drop MTU size a bit which fixes +# the scenario altogether. When we discover why this is +# happening, we should remove the MTUBytes line. +MTUBytes=64000