PingAck did not arrive in time | Initial packet S crossed

This article will help you tune DRBD when you're seeing continuous disconnections across busy or low throughput links.

If you see these messages in the logs:

May 26 13:54:07 node-0 kernel: drbd r0: initial packet S crossed

                                                                            - or -

May 26 13:54:07 node-0 kernel: drbd r0: PingAck did not arrive in time.

or DRBD® continuously disconnects after successfully connecting for a short time try adding the following to the net section of the affected resource:

net {
  timeout 90;
  ping-timeout 20;
  ping-int 15;
  connect-int 10;
}

If the problem persists, consult the `drbd.conf` man page for more details about each section and tune them accordingly and/or ask the admin to verify their network is healthy and is performing as well as they would expect.

Reviewed 2020/12/07 – DGT