Earlier today, around 2:30pm PDT, Linode informed me of a hardware issue on the server that runs our node. They were required to take us offline for approximately 20 minutes in order to effect repairs to the software that controls their RAID array.
The node rebooted itself when they were done and everything seems to be in order.
Unfortunately due to having no A/C in my room I was unaware of this issue until the time of this post, or I would have mentioned it sooner. I hate summer.