How can I change the default log level from my Monero daemon?

Question

How much of an impact will my log level have on syncing time? Are there any security concerns with using a log level of 0 or 1?

Answer 1

Use the --log-level X argument to bitmonerod. Default log level is 0 (less verbose).

The impact on syncing time is minimal on 0, but it can be significant when using a very verbose method like 4, and if you are writing to a log file on the same disk where the blockchain is downloaded.

Logs mostly have network information, so I'd say the security impact is minimal. You can completely disable logging if you are concerned by directing output to /dev/null if you are on Unix-like OS.