Relationship Between Common Init.ora Parameters and Unix Kernel Parameters

Note:144638.1

Purpose

The following table documents Unix kernel parameters that should be monitored and possibly increased after changes are made to the related init.ora parameter. Please check with your Operating System documentation for specific details on the parameter changes.

Init.ora Parameter	Unix Kernel Parameter
db_block_buffers	shmmax
db_files (maxdatafiles)	nfile, maxfiles
large_pool_size	shmmax
log_buffer	shmmax
processes	nproc, semmsl, semmns
shared_pool_size	shmmax

Common Unix Kernel Parameter Definitions

The following Kernel Parameters tend to be generic across most Unix platforms. However, their names may be different on your platform. Consult your Installation and Configuration Guide (ICG) for the exact names.

maxfiles - Soft file limit per process.
maxuprc - Maximum number of simultaneous user processes per userid.
nfile - Maximum number of simultaneously open files systemwide at any given time.
nproc - Maximum number of processes that can exist simultaneously in the system.
shmmax - The maximum size(in bytes) of a single shared memory segment.
shmmin - The minimum size(in bytes) of a single shared memory segment.
shmmni - The number of shared memory identifiers.
shmseg - The maximum number of shared memory segments that can be attached by a process.
semmns - The number of semaphores in the system.
semmni - The number of semaphore set identifiers in the system; determines the number of semaphore sets that can be created at any one time.
semmsl - The maximum number of sempahores that can be in one semaphore set. It should be same size as maximum number of Oracle processes.