Linux Performance
The issue with performance is that junior sysadmins and developers start flipping knobs thinking that the defaults are somehow holding them back.<p>The truth is usually there are tradeoffs and the defaults fit a broad general case.<p>If you want throughput there are tunables for that, if you want low latency then usually those are inversely correlated. Same for tuning for low data loss after failure and so on.<p>You have to spend time learning the tradeoffs, which sysadmins used to do- now nobody has time as they have been munged into one role at many places.