On a Cisco device, I know that enabling debugging can incur a performance hit since debugging has such a high priority on the CPU. I know that to log debugging, you have to set logging up to the debugging level (logging buffered 4096 debugging, for example) and also enable debugging on some feature.
Does configuring the logging debugging incur the performance hit even if you don't enable debugging on some feature, or would it be safe (assuming you want and can handle all the logging events via syslog) to configure 'logging buffered 4096 debugging' to have maximum logging available if/when someone uses debug?
No, the final word in
logging buffered 4096 debuggingis just what log level is the lowest actually kept, so unless you have debugging enabled, there is no CPU impact.