The maintenance took more time than anticipated because one of the server failed to reboot due to a problem in RAM. We needed to debug physically this server until we knew it was totally broken. Then, we swapped the bad server with a working server in order to end the maintenance. Now everything is fine in Paris datacenter.
We are going to upgrade the host OS of all machines in the Paris datacenter. Each machine will be reinstalled one at a time. During the re installation, the VPS will be down. The re installation of a machine takes around 10 minutes. The full operation should last less than 2 hours.