Upcoming network-wide maintenance/reboot on Sep 14 2:30am PT

Tohru Adachi

Can't take a joke
Administrator
#1
via NFOServers Event System:

NFOServers Event System said:
We are planning to reboot the machine hosting your VDS at approximately 2:30am Eastern Time on September 14, in order to apply critical Intel microcode and Xen updates to address a new speculation-related vulnerability (Foreshadow/L1TF).

We have avoided the need for other reboots over the last year by using the Xen livepatching functionality to update running code. Because this specific new flaw requires the application of updated microcode at boot-time, and because its Xen code updates cannot be patched into a running system, that was not possible in this case. We plan to continue avoiding reboots on our end as much as possible in the future.

As part of the fix for Foreshadow/L1TF, we are also being forced to disable hyperthreading (SMT) globally for our machines. This means that customer virtual cores can no longer be assigned to exclusive hyperthreaded cores. However, our systems have such low overall CPU usage that customer VDSes with heavy CPU usage on specific virtual cores usually have them assigned to physical cores with very light-usage neighbor threads by the Xen scheduler already, essentially turning virtual cores into full physical cores. As a result, we expect (and have so far observed) minimal, if any, performance impact from the switch away from SMT. If you do notice reduced performance after the maintenance or see unusual CPU usage on your VDS (now also visible through newly-added CPU usage graphs on the "Server usage" page), please contact us, and we can explore a possible move to a different physical machine.

We also recommend that all customers take this opportunity to apply the latest security updates from their OS distributions. The vendors for all currently-supported operating systems have released patches for the new vulnerability.

For the reboot, your VDS will need to be shut down for approximately 15-30 minutes. We will attempt to gracefully shut it down on our end through Xen, but sometimes this doesn't work perfectly, so we advise that you turn off applications that might write to disk before the maintenance event. If you are running Windows 2012 R2, please also note your VDS may need additional reboots to work properly, due to a bug within Xen related to how it boots up (that only occurs during bootup) -- our system will attempt to detect when this is the case and perform the extra reboot operations, but we recommend checking afterward yourself, as well.