Each of these servers have their own databases for each region that house the information for the characters that play on them. This is due to the fact that there's way too many players taking part in D2R Items  to just continually upload everyone's data to a singlecentral location.

"Most the actions you perform in games are executed against this regional database since it's faster and your character is locked for security reasons to preserve the integrity of your individual character's records. Global databases also have backup in the event that the main fails."

The regional databases are periodically able to transmit information into the central database in this way Blizzard keeps a single database (with backups) of your thicc Level 88 Barbarians, Necromancers and other. It sounds well until that central database becomes overwhelmed and the entire system, just like the engineers that work on it, requires a rest.

"On the morning of Saturday, Pacific time, we experienced an outage across the globe due to an unexpected, substantial increase in traffic. It was a first-ever level which our servers had not ever experienced and not even when they were launched," Blizzard explained.

This was exacerbated due to an update that we released earlier in the day that was designed to boost performance around game creation. Both of these factors increased the load on our database Diablo 2 Resurrected buy items which caused it to slow out. We took the decision to roll back that Friday update, which we'd previously rolled out, hoping that would ease the load on the servers going into Sunday and also giving us the space to explore the root of the issue.