"syslogd" process taking 100% CPU under Mac OS X 10.5.4
Wednesday, July 2nd
After updating to Mac OS X 10.5.4, users have found that the process "syslogd" is swamping the CPU, causing the computer's fans to spin excessively and resulting in poor overall system performance.
As described by Apple Discussions poster benevision:
"After updating to 10.5.4 update everything is very s-l-o-w. With Activity Monitor running I can see the CPU is running at 100% just about all the time. The top process in the list is #13 "syslogd" (root). Close second is bzip2 (root)."
The "syslogd" process is a utility that the OS uses to turn over system log files by using the "bzip2" utility to compress them and creating new ones when the files get to a certain size. This helps conserve space and makes it easier to search log file contents.
While this problem has been reported by some as being associated with the Mac OS X 10.5.4 update, it is known to occur in all versions of Leopard and its exact cause is uncertain. Regardless, the problem appears to reside with syslogd's interactions with the Apple System Log facility database; removing that database appears to fix the problem. Additionally, users have found that removing and recreating the system.log file also may help the problem.
Fixes
Remove the Apple System Log database Open the Terminal (located in /Applications/Utilities and run the following set of commands:
- sudo launchctl stop com.apple.syslogd
- sudo rm /var/log/asl.db
- sudo launchctl start com.apple.syslogd
These commands stop the syslogd process and then remove the database, then restart the process again. It is unadvisable to remove the database while the process is running. If the CPU still begins running at 100%, try applying the second fix.
Remove and recreate the system.log file
In the terminal run the following set of commands:
- sudo launchctl stop com.apple.syslogd
- sudo rm /var/log/system.log
- sudo touch /var/log/system.log
- sudo launchctl start com.apple.syslogd
That being said, I did run into this exact problem a few dot-releases ago. It turned out to be a bug in Little Snitch trying to write several log messages per second. Disabling, then upgrading, Little Snitch solved the problem for me.
As the previous commenter said, check your logs and see if a particular process is hammering them. It's more likely that another app is at fault. Disabling or removing syslogd is not recommended, as it prevents anything and everything on your system from logging.
- by Mark Douma July 2, 2008 6:00 PM PDT
- As BriEnigma said, syslogd doesn't handle rotating the logs, it handles the entire system logging process itself. It is, as its name implies, the "system log daemon" (most of the *nix-related processes that launch earlier on during boot and end with a "d" in their name represent a daemon-type process).
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(3 Comments)I've run into this type of syslogd-cpu hog behavior before as well. In my case, it was caused by a QuickTime plugin logging the same error message thousands of times a second. syslogd always stores the primary logging information in the asl.db database file, and then is responsible for also converting the information stored in the database and updating the system.log. Originally I tried to fix it by deleting just the system.log, which had little effect, as syslogd went right back to trying to convert all of the info in the huge asl.db back out to the system.log. I also had to delete the asl.db file as well, which I did in single user mode.
It might be helpful to temporarily save the system.log instead of outright deleting it in that it could be helpful to determine what was causing all of the excessive error messages/logging in the first place.
Hope this helps.......