"http first read error: EOF" errors from WordPress backend

[Mattias Geniar]

> -   FetchError     http first read error: EOF
> -   BackendClose   21 reload_2017-03-21T100643.default
> -   Timestamp      Beresp: 1490916389.664967 60.000557 60.000114
> -   Timestamp      Error: 1490916389.664978 60.000567 0.000011

At the risk of repeating myself: try to disable gzip & any wordpress plugins that might be trying to gzip on their own (aka: output buffering in PHP).

To me, this seems like Varnish is waiting for the backend to send more data, because it replied with a certain Content-Length header but sent a few bytes less than it advertised, and Varnish is waiting for those missing bytes.

Mattias