On December 2nd and 3rd, 2017, Salesforce experienced a service disruption on the following instances: EU5, EU14, EU15. The disruption started at 11:49 pm CET, Dec 02 and ended at 12:09 am CET, Dec 03. The instances were disrupted again at at 12:30 am CET, Dec 03, which was resolved at 12:55 am CET, Dec 03. The final disruption started at 12:58 am CET, Dec 03 and was finally resolved at 1:18 am CET, Dec 03. The total duration of the degradation was 1 hour and 5 minutes.
The performance is up and running again. Salesforce mentioned the following root cause: "The problem was caused by a configuration error introduced during routine maintenance. The configuration error was corrected and normal service was restored."
At 1:30 am CET on Dec 03, the maintenance has been extended beyond the scheduled window. During this period (Duration: 46 minutes) the Salesforce service was available in Read-Only mode. After that a service disruption occurred at 2:16 am CET, Dec 03, which caused end users being unable to access the service. The service disruption was resolved at 3:10 am CET, Dec 03. The disruption lasted 54 minutes. The root cause of this incident is currently under investigation.
To monitor the performance yourself, you can visit the Trust page provided by Salesforce. You can also subscribe for notifications per instance. On this page you can find the information provided regarding this service disruption.