Everything seems to be working again. I got an email from my host today:
Thank you for being patient with us while we restored services on our server farm.
The issue was a failed cache module in the shared storage array and it took time to diagnose, order the replacement part, and then make sure all systems were 100% back before we re-enabled access.
At this time all services are completely restored, however it may take some time for any emails that were not able to be received to be re-delivered. This may take 1-2 days under normal circumstances. We will continue to closely monitor all systems in case there are any lasting effects from the outage.
All customers will receive a 3 month service credit (applied to the end of their current contract) for the disruption.
We appreciate you sticking with us through this unusual and trying situation. We strive to provide the most cost effective solutions with adequate redundancy to prevent data loss.