It's been a shaky couple of days over on the EUW servers. Lots of server unavailable, discounts, and all sorts of other nasty stuff. Riot hasn't been ignoring the problem though!
We were hoping to give you a rundown of the problems over the weekend today, but the root cause has been very difficult to identify. We have got a team going through every aspect of EUW infrastructure and they’ve been working constantly on the issue.
The main issue is that it strikes seemingly from nowhere in a 5-30 second flash, causes a chain reaction of problems and then resolves itself. However it leaves behind a login queue and other lingering issues which then also take time to resolve themselves giving the impression that this is of a much larger scale. We have a lot of monitoring systems in place to catch this transient state, and just so you guys know we have not stopped searching between the problems.
We’ve currently narrowed this down to one aspect of the infrastructure and are working on that right now. To answer one question that has come up quite a lot, this is not caused by the amount of players, external attack or platform limitations; that would be very easy to nail.
We’ll keep you in the loop as more information comes to light, particularly when we believe we’ve found the heart of the problem. We know it sucks and we’re working flat out to find the source and eliminate it."
Immediately following this, an emergency network maintenance, for EUW, was announced.
Here is the Riot NOC post:
We are planning to do an emergency network maintenance to address the recent issues, this will require downtime. We will be starting in a few hours but not sure on the exact time. We will message out prior to beginning the maintenance."