An engineer is en route to investigate the issue.
We will update the post as soon as we have more information.
Update 5:30AM : The filesystem require an fsck to be performed on it to correct some inconsistencies. Unfortunately we would not have an estimate on completion at the current time however, we will update the post as soon as we have one.
Update 5:40AM : The fsck is 50% complete, the estimated time for completion is 6:20AM
Update 6:00AM : The fsck completed and all services resumed.