Mac OS X Server v10.6: Understanding process limits
In versions of Mac OS X Server prior to version 10.6 (Snow Leopard) the maximum number of processes available on a server was limited to 2500. The 64-bit kernel included in Mac OS X Server v10.6 automatically scales the maximum number of processes, vnodes (open file handles), and threads based on the amount of memory installed in the server.
Mac OS X Server 10.6
For hardware that supports the 64-bit kernel, the following limits are automatically set by the operating system based on the amount of memory present:
- For each 8GB of installed memory, 2500 processes and 150,000 vnodes are available. The maximum number of threads is set to five times (5x) the number of maximum processes.
- A single user ID (uid) can use up to 75% of the maximum number of processes.
- A single process can allocate up to 20% of the maximum threads value.
The following Terminal commands can be used to read the values on the running system:
This table details the expanded limits as memory is added to a Mac OS X Server v10.6-based server:
|Memory in GB||Maximum # of Processes||Maximum # of vnodes (open files)||Maximum # of Threads|