Process Sizing Tunables

maxusers (Solaris 7 Release)

Description

The maxusers parameter drives max_nprocs and maxuprc.

Data Type

Signed integer

Default

Lesser of the amount of memory in Mbytes and 1024

Range

1 to 2048

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Note -

Values greater than 1024 must be specified in /etc/system. If a value greater than 2048 is provided, calculations clamps the value at 2048, but later processing sets the value to the provided value.

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Units

Users

Dynamic?

No. After computation of dependent variables is done, maxusers is never referenced again.

Validation

None

When to Change

If the default number of user processes derived by the system is insufficient. This insufficiency is seen by the following messages on the system console or messages file.

out of processes

Commitment Level

Unstable

max_nprocs (Pre-Solaris 8 Releases)

Description

Maximum number of processes that can be created on a system. Includes system and user processes. Prior to the Solaris 8 release, the value was determined by computation and then used in the setting of maxuprc.

This value is also used in determining the size of several other system data structures. For releases prior to Solaris 8, if a value is provided in /etc/system it is used rather than the computed value. Other data structures where this variable plays a role are:

• Determining the size of the directory name lookup cache (if ncsize is not specified)

• Allocating disk quota structures for UFS (if ndquot is not specified)

• Verifying that the amount of memory used by configured system V semaphores does not exceed system limits

• Configuring Hardware Address Translation resources for the sun4d, sun4m, and Intel platforms

Data Type

Signed integer

Default

10 + (16 x maxusers)

Range

266 to value of pidmax

Dynamic?

No. max_nprocs is assigned to the v_proc element of the v structure after the initial parameter calculation is completed. Changing v.v_proc on a running system almost certainly results in a system crash or silent data corruption.

Validation

Compared to maxpid and set to maxpid, if larger. On the sun4d and Intel platforms, an additional check is made against a platform-specific value. max_nprocs is set to the smallest value in the triplet (max_nprocs, maxpid, platform value). Both platforms use 65,534 as the platform value.

When to Change

Starting with the Solaris 8 release, this value can be changed to enable more than 30,000 processes on a system. Changing this parameter is one of the steps necessary to enable support for more than 30,000 processes on a system.

Commitment Level

Unstable