For dark scenes, the histogram will usually be weighted to the left, and that can be perfectly normal. What matters is not making it look “balanced,” but placing exposure to match your intended final image.

A good rule is still to expose as far right as you can without losing important highlights. In a dark concert or night scene, that often means a large peak on the left from the dark background, plus a smaller amount of data extending toward the right for the lit subjects. If the histogram never reaches far right at all, the image may be more underexposed than necessary.

Some highlight clipping can be acceptable—especially stage lights or specular highlights—if avoiding it would force the whole image too dark.

To keep noise low in RAW, capture as much exposure as you safely can, then make the image darker in processing by raising the black point and adjusting shadows/blacks. That helps hide noise in areas intended to be near-black. Posterization is mainly a risk if you severely underexpose and then try to brighten shadows too much later.

So: left-heavy histogram is expected, protect important highlights, allow unimportant bright lights to clip if needed, and set the final darkness in RAW processing.