[Resolved] Storage Maintenance

To correct problems we have identified in our storage systems, we need to perform corrective maintenance procedures tonight between 23:30 and 3:30 CET. This will impact some of your server systems, making certain data volumes unavailable for a period of 15 to 20 minutes.
We recommend that you do not restart your servers during this period. All services should return to normal immediately following the termination of the maintenance window.
If you will be affected by this maintenance, you should have received a mail from us advising you of the issues and timing.
We will update this post to keep you informed of our progress.

Edit 23:30 CET: operation started

Edit 00:32 CET: first reboot done, equipment beeing behaving as expected, we proceed further

Edit 01:00 CET: most reboots are now ongoing, our first upgrades having been successful

Edit 01:30 CET: most of our storage units have been upgraded – if your server recovered from I/O stalls, this issue is fixed for you — otherwise, this upgrade will be finished in the next hour

Edit 01:34 CEST: a compute node crashed during this operation, we are starting the affected virtual servers on another machine right now.

Edit 02h30: maintenance is finished, thank your for your patience during this operation.