World of Warcraft has announced some details about the recent server upgrades. I have snipped the important stuff below.
Last Thursday we made our first such upgrade. 20 of our 88 realms were moved off of the original hardware and placed on a new hardware configuration. These 20 servers initially performed very well, up until we reached our maximum concurrency Friday evening. The high population numbers uncovered an issue in the new backend shared infrastructure. This issue caused some players to experience severe lag and disconnects on a few of the realms, making them virtually unplayable.
In order to stabilize the affected realms and allow as many players as possible the ability to continue playing, we lowered the population caps by 30%. This stabilized the realms to the point where 70% of the players on the realms in question could play, but it also resulted in large queues.
The problems were attributed to high concurrency numbers on individual realms putting extreme stress on the backend infrastructure. We were able to address this problem by implementing additional hardware into the infrastructure this afternoon. This additional hardware has allowed us to stabilize the affected realms, and thus increase the server caps. We will continue to monitor the performance throughout the evening. If we notice any of the performance issues starting up again we will lower the population cap level enough to stabilize performance.
They also announced a 48 hour free time extension:
We do appreciate your patience and enthusiasm about playing World of Warcraft, and we regret that you faced periods of high traffic this past weekend that caused some of you to have a poor game experience. So, due to the extended nature of the server issues, we will be providing a free 48-hour extension of play time. As with previous extensions, this will show up as free extra time on your current billing period (or on your trial period, for those of you who purchased the game recently). We hope you’ll bear with us as we continue to work hard on implementing changes for long-term stability.
This brings my free time up to 8 days.