Both. The new worlds will be primarily for new characters, but they'd rather go ahead and resolve the infrastructure problems on the existing worlds than force people to leave if they can.
I haven't seen anything from SE stating they'll be expanding the capacity of the current worlds, only adding new ones. Yesterday, Yoshi-P (and someone else) released a lengthy statement that seemed to confirm this.
Catwho, you seem to have a lot of IT knowledge. What have you seen from them that you'd consider to be confirmation that they're expanding the capacity of current worlds (other than just using what should be common sense)?
I'm not trying to be difficult, I just really want to feel better about all of this.
I'm pretty sure I remember reading in one of the Yoshi P comments that they're adding in infrastructure not only for extra worlds, but for the servers to handle more connections, period. For example, the cross-server Duty Finder simply couldn't handle the number of requests hammering it - they had two servers dedicated to it and split the DF applicants into two pools, but now they're going to split them into more. This was one of the stability issues that caused the 90000 error and problems with instances. Adding in more Duty Finder servers will allow them to increase the capacity of people across all worlds as well as individual worlds, both new and existing. Edited, Aug 30th 2013 2:24pm by Catwho
Each FINAL FANTASY XIV: A Realm Reborn World server has been designed to support a maximum of 5,000 concurrent connections. This is not the maximum number of characters which can be created on a World, however, but the maximum number of characters which can be logged into that World simultaneously. When more than 5,000 characters log into a World at once, there is a higher risk of server crashes and login errors. The restoration of crashed servers is usually followed by a rush of players attempting to log back in, which, in turn, puts a strain on our lobby server, and can ultimately have an adverse affect on all of the Worlds.
Direct from his latest comments. Yoshi stated that more than 5,000 concurrent connections causes instability on the world server. He then said they are preparing additional worlds.
In addition to increasing the number of Worlds, we are also optimizing the Duty Finder (party matching) management servers in an effort to reduce server load and ensure better stability when using this feature.
To address Duty Finder, they are planning to break the worlds into more than the two groups (JP and NA/EU) for the purpose of Duty Finder matchups. Each server will belong to a group of servers DF will pull people from. In other words, DF won't find ANY player (global), but only those in your server group.
Currently, the Duty Finder servers split our data centers into two groups of 25 Worlds, and then do the party matching from players from within the same data center. We have determined that by adding new Worlds, the Duty Finder servers will not be able to process the additional data as long as there are only two pairings of groups to match from. Therefore, we have decided to create additional groups to alleviate this problem before it occurs, and by doing so, reduce the burden on the Duty Finder servers, and ultimately allow more players to access the feature.
I expect the infrastructure to include new worlds, with the possibility for World Transfers to redistribute the population.