NicoAdrian's questions

Here is my Varnish conf:

/usr/sbin/varnishd \
      -a 127.0.0.1:6081 \
      -T 127.0.0.1:6082 \
      -f /varnish/default.vcl \
      -P %t/%N/varnishd.pid \
      -s malloc,4G \
      -p thread_pools=12 -p thread_pool_min=250 -p default_ttl=1 -p default_grace=0 -p timeout_idle=1800

So 12 * 250 = 3000 threads. With this setup, I end up with more than 400k open files.

Reducing the number of threads to the minimum does indeed reduce the number of open files a lot.

Question is: how is that possible ? is it normal that each Varnish thread takes so much open files ?

EDIT: Here's my VCL file:

vcl 4.1;

backend someBackend {
    .host = "someBackend.net";
    .connect_timeout = 2s;
    .first_byte_timeout = 5s;
    .between_bytes_timeout = 5s;
}

sub vcl_recv {
    # Remove Varnish from X-Forwarded-For (set by Nginx)
    set req.http.X-Forwarded-For = regsub(req.http.X-Forwarded-For, ",[^,]+$", "");
}

sub vcl_backend_fetch {
    # Hide Varnish token
    unset bereq.http.X-Varnish;
}

sub vcl_backend_response {
    unset beresp.http.Vary;
}

sub vcl_deliver {
    unset resp.http.Via;
    unset resp.http.X-Varnish;
}

On my CentOS 7 server, the load on each core is unequally distributed, as seen in the screenshot: some nginx worker seem to take way more load than other. irqbalanceis enabled, hyperthreading disabled.

Any idea why ?