The xmission.com mirror (U.S. -- Salt Lake City, Utah) is currently down due to hardware maintenance. They expect the server to be down for "the next few days." One of xmission's customer service representatives confirmed this via a live chat session.
I've been having trouble connecting to the mirror the past day or so, and I decided to contact the company to see if they could provide an explanation. (I was a bit surprised by the outage because xmission has performed reliably for me.)
We are currently experiencing technical difficulties with our mirror.
UPDATE: 2018-04-26: We have rebuilt a new storage server for our mirrors with new drives and a new ZFS pool. The prior pool was corrupted due to faulty hardware and a rare ZFS on Linux 0.6.5.6 bug shipped with Ubuntu 16.04 LTS. Instead of using the Ubuntu packages, we are building the SPL/ZFS kernel modules from source, and using the latest version, which is 0.7.8. Ubuntu and Debian have been prioritized for getting synchronized first, and are currently in progress. Please stay tuned, and thank you for your patience.
Our ZFS pool that stores the mirrors lost a drive, and replacing the drive led to some technical problems, likely related to faulty RAM modules. Our system administrators are currently working on the problem, and will have mirrors.xmission.com back up soon. Please update your systems using a different mirror, and check back with us later.
Para la arquitectura x86 (32-bit), no hay nada por actualizar, Espero.
Thanks for posting the more detailed explanation of what happened with xmission's mirror(s). I dug a bit more within the company's website and noticed that they have a Twitter feed where they post system status updates:
