All of the Store Locator Plus® web properties are now living on an updated server cluster. The new configuration, a load-balanced cluster, will provide zero-downtime maintenance window and faster performance under peak load; These upgrades will be most noticeable for our SaaS users.
Our prior server configuration used a failover configuration. In that type of configuration a web server handles 100% of the load and if it fails a second duplicate server that is in standby takes over. This provides limited downtime with reduced costs; However, it also means there are routine service outages when the underlying software (Operating System, web services, web apps) are updated.
The current configuration, put into place over the weekend with zero downtime, uses a load balanced configuration. In this configuration two-or-more servers mirror each other and are all online and answering web requests at the same time. Requests are split between the servers with a goal of maintaining an average load of just under 50%. This ensures that if one server fails the service stays up-and-running while a replacement server is automatically brought online to assist in web services.
The load balanced cluster also provides an added benefit of horizontal scalability. Failover style server could only be pushed up to a bigger server with more CPUs and RAM and faster network interfaces; a process that meant building ever-bigger servers with higher costs and longer maintenance window downtime. The load balanced cluster configuration monitors server loads across the cluster and adds a new server automatically at set performance limits. This ensures that there is a less-than-5-minute response time to adding capacity whenever there is a spike in usage.