Mac OS X: Fix High CPU Usage by syslogd

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.)

syslogd

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.

9 Responses to “Mac OS X: Fix High CPU Usage by syslogd”

  1. Sean O'Brien  on September 2nd, 2008

    THANK YOU!!!! I have been looking for a solution to the problem all night. Some didn’t work and others were way above my knowledge. My computer has been so slow and this totally took care of it. Honestly, THANK YOU SO MUCH!!!

  2. Jabba the Hut  on September 3rd, 2008

    Thank you! That worked great!

  3. Samantha House  on September 28th, 2008

    This worked perfectly!

  4. Tomàs  on October 20th, 2008

    Thank you! Same problem like you and same solution applied. Now everything’s working well!

  5. Lynne  on November 28th, 2008

    Yet another big thank you! Fan shut down seconds after moving the gigantic file.

  6. dan mcweeney  on December 20th, 2008

    This just fixed my runaway syslogd process! I have been killing the process for months, trying seeing nothing in the logs. This seems to have fixed it, BTW, my asl.db was 373M.

    thanks for the tip.

  7. Will  on December 23rd, 2008

    The same works for many other haywire root software problems, as well as renegade 3rd party issues.

  8. Martin  on December 28th, 2008

    Thanks, fix worked perfect.

    macbook:~ martin$ sudo file /var/log/asl.db
    /var/log/asl.db: data

    I’m guessing that means it’s either corrupt, or just shows that using massive binary blobs is a bad idea. I was using Instruments to debug some C code on 10.5.5, so I figure that might have pushed it.


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