And from the site itself:
The recent major downtime, initially started as a brief maintenance downtime by schedule, was a result of three unforeseen issues:
1. Hardware problem: the UPS powering the server depleted its battery and was taken down, which later resulted in the premature death of the server's sole (regrettably non-redundant) power supply. The server's motherboard is old and turned out incompatible with the spare power supply that I had at hand, so it took me some time to obtain a proper replacement one.
2. Software problem: we switched the Linux kernel trunk during the maintenance period, which had broken networking (at least in our setup.) Now that we switched the trunk to the newest 4.* version, everything is fine.
3. Our exit point server provider (an ad-hoc reverse proxy of sorts) terminated service for us on the grounds of GUROchan's content breaching their terms of service. We found a new reverse proxy provider and are in the process of setting up networking with them. The new reverse proxy is expected to enter service within a couple of days from now.
We are really sorry for this mess. In order to prevent reverse proxy problems in future we will set up more exit point servers to achieve fault tolerance through redundancy, and also (coarsely) balance the networking load via a simple DNS round robin. So, we are calling for your help: if anyone can and is willing to provide a reverse proxy service (* see the note below) for us, please contact me (enclaved) or ryonaloli either on IRC or start a thread in /dis/. Your help will be greatly appreciated and will help ensure GUROchan stability and longevity. This resource is very dear for us and all of our users, so we will continue to run it by any means.
—enclaved
_
* Technical note: in our ad-hoc context, a reverse proxy is composed of a network tunnel connecting the exit point and my border router carrying IPv4 as payload (tunneling options include GRE, MPLS, IPIP, and IPsec; the former two are preferred) and PATPost too long. Click here to view the full text.