The activation of signer machine was successful, all pending certificates were processed in the last hours.
Short version: There is a visit at the datacenter planned to enable the signer again (and do some other maintenance there).
Unfortunately it was not possible to get the signer back to work again during the last visit due to a hardware-issue with the harddrive.
To get the server running on the (pre-)created backup drive did fail, too …
Therefore we took the time during the last weeks (when it was not possible to visit the datacenter due to different business and personal reasons) to rebuild a test-environment on spare hardware and to train ourselves.
We should now be able to do the necessary steps to bring back the signer machine to work.
In the background we’re currently adjusting our processes to make it easier to visit the datacenter during out-of-office-times (as every trip to the datacenter takes several hours additionally to the time we’re working at the servers).
In future we plan to set up an additional confuguration, which can take over in case of a failure in the datacenter, but this will still take time. However: The exact procedure needs to be worked out as the machines are not to be connected to the internet, but need to communicate (e.g. for CRL-creation, certificate serial numbers etc.).