Varnish VMods for Version 6.1?

Dridi Boukelmoune dridi at
Thu Sep 20 09:18:48 UTC 2018

On Thu, Sep 20, 2018 at 10:22 AM Winkelmann, Thomas (RADIO TELE FFH -
Online) <t.winkelmann at> wrote:
> Thanks for the feedback. We tried 6.0.1. So far H/2 seems to be working fine under normal conditions. But as soon as the request are increasing ( > 800 reg/s) the traffic will stop. Also HTTP 1.1. traffic. Sound like these two problems:

2418 may very well be responsible. You could try working around this
by adding more worker threads to your pools. That would postpone
the deadlock to higher concurrent traffic. And possibly increase the
thread reserve as well.

> Let us know if we can help to solve these problems.

I'm afraid we already have a consistent reproducer, so I guess all
that remains is that we (Dag) roll up our (his) sleeves and do
something about it. Joke aside, we've looked at it then but it's not
an easy task.

In my previous message I said:

> so ignore varnish-modules for now, please be aware of this before
> choosing one.

What I really meant was:

> so ignor[ing] varnish-modules for now, please be aware of this before
> choosing one.

In other words, once varnish-modules supports 6.1, please consider
that 6.0 is an LTS series before you pick your target. Not that there
is anything wrong about picking 6.1 if you are planning to periodically
have major upgrades (I wouldn't recommend staying on an
unmaintained branch once it reaches EOL).


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