The database services underpinning the Esri UK Online Services will undergo a system upgrade on Sunday, 11th November 2012, between 03:00 and 03:30 – there will be a slight disruption as the database will need to be rebooted and unavailable for a few minutes.
Details from Amazon Web Services (AWS)
The Esri UK database services use AWS as their provider.
Amazon Web Services are applying a mandatory system update for all Amazon RDS for MySQL and Oracle DB Instances within your user-defined maintenance window as per the following schedule:
The updates will be applied to our DB Instances during their scheduled maintenance window that falls within the start and end dates stated above for the region in which they are deployed.
Please note that this is a system upgrade and not a database software (DB Engine Version) upgrade.