Recently, I’ve been experiencing a high CPU usage by the process syslogd in Mac OS X 10.5.2 Leopard, coupled with strange Console.app behavior. If you’re experiencing this as well, give this a shot and see if it works (at your own risk.)

FIrst, you should check if this is a problem on your system, which is usually caused by large asl.db files. Open Terminal.app (Applications/Utilities/Terminal.app) and enter the following:

du -hs /var/log/asl.db

and hit enter. If it shows that your asl.db file is pretty huge (mine was 80MB) you’ll want to run this fix. If it isn’t, a rampant syslogd is probably not due to the asl.db file, but instead some application doing a lot of logging. Open Console and look if there’s any applications that are logging a lot, like if you see “ — last message repeated 500 times —”, that’s probably what is causing syslogd to own a lot of CPU.

If asl.db is huge, do the following. You’ll first have to enable a root user to your system. Then, go to Terminal, and enter the following (enter one by one, and hit enter afterwards):

sudo launchctl stop com.apple.syslogd
sudo mv /var/log/asl.db /var/log/aslold.db
sudo touch /var/log/asl.db
sudo launchctl start com.apple.syslogd

You will be asked to enter the root password on the first command, while subsequent commands will automatically be authenticated as root.

Once you do this, the syslogd process should restart, but the CPU it uses should be next to nothing. Hope this helped.