Blizzard is rolling out new hardware for
several US realms this Thursday, and the process of transferring the realms means - you guessed it, extensive
downtime. The migration will begin on Thursday at 12:01 AM PST and may last as long as 24 hours. Those of
you on effected realms will receive an extra day's credit to your account, which is, I suppose, better than
nothing. Following the migration, Blizzard plans to open character transfers from existing realms to new realms
(yet to be opened) to further help with performance and overcrowding issues.
Realms transferring to new hardware are Archimonde, Dalaran, Khadgar, and Mal'Ganis.
Other affected realms include Aggramar, Andorhal, Anetheron, Burning Blade, Burning Legion, Dentarg, Duskwood, Earthen Ring, Eonar, Eredar, Executus, Gilneas, Gorefiend, Haomarush, Kargath, Laughing Skull, Lightning's Blade, Llane, Malygos, Scilla, Shadow Moon, Steamwheedle Cartel, Thunderhorn, Thunderlord, Turalyon, Ysera, Ysondre, and Zuluhed. While these realms are not receiving a hardware upgrade, Tseric explains that current equipment configuration requires this.
Update: The schedule has been pushed back to Thursday.