A recent Microcode update for Intel CPUs basically turned our i7-6850k into an i7-6850 (locked multiplier) reducing the speed of the CPU substantially.
This platform does not require the Linux Microcode anyway as the Microcode provided by the BIOS is already not vulnerable to meltdown and spectre exploits.
In order to restore full operating speed a reboot is necessary to back out this microcode upgrade. This machine provides the /home directory for all machines here and also the following shell servers: centos7, fedora, mint, opensuse, scientific, and ubuntu, as well as our web server.
Anyone logged into those shell servers will be disconnected as they reboot and any home directory I/O will freeze for several minutes on all the other machines.
This work is scheduled for 1AM and should conclude by 1:15AM if all goes according to plan.