As for installing the updates, for the major updates the server NEEDS to be offline.. just like windows has to close, or at-least restart any program when trying to install an update, the server cannot update the files if the game is up and the files are in use. Also, if people are online when the patches are being installed, there is a much higher chance of problems occurring, lost stats, missing items etc.
Yes ofc but there alot of games that can install the patches without affecting the game, until the game is restarted.
And im not the most IT and server pro in the world, but im pretty sure that a modern server can reset a cache memmory pretty fast.
There must be a way to upgrade to a new main server to speed up the downtime. Allods may not have that many players online but the game
just consumes money from the few players that play this game. so i mean there must be any way to shorten the downtimes.