Pantheon Operations
Update - This is a follow up to our last week’s update on Meltdown/Spectre vulnerabilities. (

As we mentioned, Pantheon is committed to ensuring security is not compromised and thus we patched the infrastructure running your PHP code with high priority. We observed a large increase in CPU utilization after updating OS kernels. Even after adding additional resources to the platform, a number of customers reported impacted performance for their websites.

We added even more CPU resources to the platform while our engineers worked diligently to identify methods to restore site performance to pre-update levels. That work has paid off and we have some good news to share with you. The patched kernel ( with subsequent optimizations is showing great results. We see significant improvement across all customer websites. As noted earlier, we might not be able to get the same output which we had pre-Meltdown/Spectre, but we are committed to making things as fast as they can possibly be.

In the coming days, our engineers will publish a blog post explaining this work in depth. Check out our blog ( if you are interested in learning more.

We appreciate your feedback and staying engaged with us.

Jan 18, 14:07 PST
Monitoring - In the recent wake of the disclosure of the Meltdown/ Spectre vulnerabilities, Pantheon has taken steps to ensure the security of our customer sites. We applied appropriate patches to the servers running your PHP code. Pantheon did the right thing for your business, however, it came with a penalty. This penalty is imposed not only on your site nor Pantheon alone. It’s a global impact - where CPU performance on patched machines has taken a performance hit, anywhere between 10%-30%. We understand it’s difficult to accept this hit, but security cannot be ignored.

We are working diligently to minimize the impact on our customers. For example, we have already provisioned additional capacity so that your website and users get the best throughput in the post-Meltdown world. It isn’t sufficient to compare last week’s New Relic graphs/performance (pre-Meltdown) and this week’s performance (post-Meltdown). We all have to acknowledge that CPUs are now slower and that affects your website performance.

If you think the performance of your site has degraded significantly and it’s impeding your users' ability to conduct business with you, do share those insights. We cannot promise next steps right now, but we are working cross-functionally to offer you the best results. Upgrading PHP to version 7.x is one step customers can take to improve performance if they haven’t already done so.

Now is the perfect time to prune away all those redundant and duplicate modules from your codebase. Check your sites’ dashboard status pages for guidance on unused modules or plug-ins. Anything that adds unnecessary overhead such as UI modules can often be deactivated in production.

If you are interested to learn more about this, here are good explanations from Cloudflare -, and The Register

Pantheon Support
Jan 10, 16:16 PST
Customer Sites   ? Operational
Dashboard   ? Operational
Global CDN   ? Operational
Spinup Operations   ? Operational
Workflow Operations   ? Operational
Support Tickets   ? Operational
Support Chat   ? Operational
Degraded Performance
Partial Outage
Major Outage
System Metrics Month Week Day
Customer Site Availability
Dashboard Response Time
Past Incidents
Jan 21, 2018

No incidents reported today.

Jan 20, 2018

No incidents reported.

Jan 19, 2018

No incidents reported.

Jan 18, 2018
Resolved - The issue with networking connectivity has been resolved. All clear.
Jan 18, 12:09 PST
Update - Our upstream provider has confirmed networking issues affecting connectivity in the US and Europe. We will update with more information as it becomes available.
Jan 18, 11:30 PST
Identified - The engineering team has identified an issue which is causing a small number of sites to be unavailable. We are working on a resolution, thank you for your patience.
Jan 18, 11:00 PST
Jan 17, 2018

No incidents reported.

Jan 16, 2018 has released version 4.9.2. This release is classified as a critical security release for all previous versions of WordPress.[1] Pantheon has made the update available for one-click update in site dashboards. We urge all users to update all environments as soon as possible. Instructions for applying core updates can be found in our Support Center.[2]

[1] -
[2] -
Jan 16, 19:30 PST
Jan 15, 2018

No incidents reported.

Jan 14, 2018

No incidents reported.

Jan 13, 2018

No incidents reported.

Jan 12, 2018

No incidents reported.

Jan 11, 2018

No incidents reported.

Jan 9, 2018

No incidents reported.

Jan 8, 2018
Completed - The scheduled maintenance has been completed.
Jan 8, 17:00 PST
In progress - Scheduled maintenance is currently in progress. We will provide updates as necessary.
Jan 5, 17:00 PST
Scheduled - Pantheon has concluded its initial testing of patches intended to mitigate the effects of the latest linux kernel vulnerabilities known as Spectre and Meltdown ( and found negligible impact to site performance.

Pantheon will begin updating the platform on January 5th at 5PM PT. Other than a brief period of downtime lasting 60 seconds to 5 minutes for non-Live environments, no other impact is expected. The update is scheduled to be complete by January 8th at 5pm PT. If you have any questions, please open a support request through the Pantheon dashboard or by emailing
Jan 5, 13:07 PST
Jan 7, 2018

No incidents reported.