As clients search mounted network volumes, the kernel_task process (pid 0) on the server is allocated more and more RAM. System administrators may notice that the amount of RAM allocated to the kernel_task process may be close to 2 GB. On servers configured with 2 GB or 3 GB of RAM, this can result in server performance degrading, or the server becoming unresponsive.

Products affected

* OS X Server (Universal) 10.4.7 or later


You can make the following change to /etc/rc.server to improve performance in this situation. This is recommended only if your server has 2 GB, 3 GB, or 4 GB of RAM.

1. Make a copy of /etc/rc.server with this command:

$ sudo cp /etc/rc.server /etc/rc.server.bak

2. As the root user, open /etc/rc.server in the text editor of your choice.

3. Locate this line in /etc/rc.server: sysctl -w kern.maxnbuf=90000

4. Change the number 90000 to 20000, so that the line reads: sysctl -w kern.maxnbuf=20000

5. Save the changes made to /etc/rc.server.

6. Restart the server.

Grande Vitesse Systems