Bukkit

When someone tp outside the border, border rejects his back, but anyway chunk make generate
It needed additional memory on SSD and looks ugly on Dynmap http://prnt.sc/acprvz

Maybe you can do something with that?
Add option, which can prevent chunk generate in <X> amount of blocks outside the border ??

The target location of the teleportation event is changed to a location inside the border by WorldBorder when someone tries to teleport outside the border, so optimally Bukkit wouldn't then generate those chunks even though the player is no longer headed there. It does anyway, though, and I can do nothing about that.

I toyed around before with preventing chunk generation outside the border as a feature, but from my testing, while it's sort of possible, it doesn't work that well in practice as the server just keeps trying to generate them over and over again.

You can of course run a Trim to clean up generated chunks outside the border.

@Brettflan: Go

Thank. I think i found the solution to ceep Dynmap clear. We just can set the visibilityLimits area, beyond which render will be disabled.