Archived - 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.
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|