NFS Server Performance and Tuning Guide for Sun Hardware

Adjusting Cache Size: maxusers

The maxusers parameter determines the size of various kernel tables such as the process table. The maxusersparameter is set in the /etc/system file. For example:

set maxusers = 

In the Solaris 2.4 through Solaris 7 software environments, maxusers is dynamically sized based upon the amount of RAM configured in the system.The sizing method used formaxusers is:

maxusers = Mbytes of RAM configured in the system

The number of Mbytes of RAM configured into the system is actually based upon physmem which does not include the 2 Mbytes or so that the kernel uses at boot time. The minimum limit is 8 and the maximum automatic limit is 1024, which corresponds to systems with 1 Gbyte or more of RAM. It can still be set manually in /etc/system but the manual setting is checked and limited to a maximum of 2048. This is a safe level on all kernel architectures, but uses a large amount of operating system kernel memory.

Parameters Derived From maxusers

Table 4-4 describes the default settings for the performance-related inode cache and name cache operating system kernel parameters.

Table 4-5 Default Settings for Inode and Name Cache Parameters

Kernel Resource 


Default Setting 

Inode cache 


17 * maxusers + 90

Name cache 


17 * maxusers + 90