Horizon Content Delivery Network Maintenance

[Update: This work was completed without incident.]

On Sunday, Aug. 16 at 1 p.m. EDT, there will be maintenance conducted on the content delivery network (CDN) that serves Horizon Javascript. We do not expect interruption to the Horizon service. The service includes the delivery of on-site content recommendations to your end users and the collection of pageview and interest data back into the Sailthru platform.

The work is the result of required maintenance by the CDN vendor used for Horizon, and we are working closely with the vendor to coordinate change timing, further mitigating risk in the change process. We have also prepared preventative rollback procedures should the vendor’s maintenance encounter any issues. A secondary CDN is active and standing by, should we need to failover in the rare event the primary vendor’s maintenance is problematic. Again, this is only a precautionary measure that we do not expect to utilize.

A successful maintenance change will last less than one hour with no interruption. If failure mechanisms need to be activated, the maintenance window could last up to 3 hours. During this time, most users would still receive content recommendations and data would still be collected and reported. Because secondary CDN activation requires a DNS change, some users would be affected by Internet Service Providers who use their own DNS caching time periods instead of respecting the DNS refresh periods set by individual domains, including those managed by Sailthru. DNS is the system that translates domains like “sailthru.com” into server location IP addresses. As these IPs rarely change, some rural and local ISPs enforce stricter caching of this data to optimize services for their users, while best practices would typically see ISPs respecting the specific settings supplied by individual domains.

We will update the Sailcast Dashboard notification inside my.sailthru.com with any updates, including confirmation of a successful maintenance window.