"Soft" limit on file descriptors that a single process can have open. A process might adjust its file descriptor limit to any value up to the "hard" limit defined by rlim_fd_max by using the setrlimit() call or issuing the limit command in whatever shell it is running. You do not require superuser privilege to adjust the limit to any value less than or equal to the hard limit.

Signed integer

64

1 to MAXINT

File descriptors

No. Loaded into rlimits structure.

Compared to rlim_fd_max and if rlim_fd_cur is greater than rlim_fd_max, rlim_fd_cur is reset to rlim_fd_max.

When the default number of open files for a process is not enough. Increasing this value means only that it is possibly not necessary for a program to use setrlimit(2) to increase the maximum number of file descriptors available to it.

Unstable

"Hard" limit on file descriptors that a single process might have open. To override this limit requires superuser privilege.

Signed integer

1024

1 to MAXINT

File descriptors

No

None

When the maximum number of open files for a process is not enough. Note that other limitations in system facilities can mean that a larger number of file descriptors is not as useful as it might be:

• A 32-bit program using standard I/O is limited to 256 file descriptors. A 64-bit program using standard I/O can use up to 2 billion descriptors.

• select(3C) is by default limited to 1024 descriptors per fd_set. Starting with the Solaris 7 release, 32-bit application code can be recompiled with a larger fd_set size (less than or equal to 65,536). A 64-bit application sees an fd_set size of 65,536, which cannot be changed.

An alternative to changing this on a system wide basis is to use the plimit(1) command. If a parent process has its limits changed by plimit, all children inherit the increased limit. This is useful for daemons such as inetd.

Unstable

Specify the amount of kernel pageable memory available. This memory is used primarily for kernel thread stacks. Increasing this number allows either larger stacks for the same number of threads or more threads. This parameter can only be set on systems running 64-bit kernels. Systems running 64-bit kernels use a default stack size of 24 Kbytes.

Unsigned long

64-bit kernels, 2 Gbytes

32-bit kernels, 512 Mbytes

64-bit kernels, 512 Mbytes - 24 Gbytes

32-bit kernels, 512 Mbytes

Mbytes

No

Value is compared to minimum and maximum sizes (512 Mbytes and 24 Gbytes for 64-bit systems) and if smaller than the minimum or larger than the maximum, it is reset to 2 Gbytes and a message to that effect is displayed.

The actual size used in creation of the cache is the lesser of the value specified in segkpsize after the constraints checking and 50% of physical memory.

This is one of the steps necessary to support large numbers of processes on a system. The default size of 2 Gbytes, assuming at least 1 Gbyte of physical memory is present, allows creation of 24-Kbyte stacks for more than 87,000 kernel threads. The size of a stack in a 64-bit kernel is the same whether the process is a 32-bit process or a 64-bit process. If more than this number is needed, segkpsize can be increased assuming sufficient physical memory exists.

Unstable

For information, see segkpsize (Pre-Solaris 7 and the Solaris 7 Release).

Specify the amount of kernel pageable memory available. This memory is used primarily for kernel thread stacks. Increasing this number allows either larger stacks for the same number of threads or more threads. This parameter can only be set on 64-bit kernels. 64-bit kernels use a default stack size of 24 Kbytes.

Available for the Solaris 7 release with patch 106541-04 or the Solaris 7 5/99 and Solaris 8 releases.

Unsigned long

64-bit kernels, 2 Gbytes

32-bit kernels, 512 Mbytes

64-bit kernels, 512 Mbytes - 24 Gbytes

32-bit kernels, 512 Mbytes

Mbytes

No

None

Increase when more threads are desired.

Unstable