Kernel Parameter configuration for Oracle Database Linux Server

If the Linux Kernel Parameter settings are inappropriate or unreasonable, Oracle may also encounter errors, such
10 GB:
SQL> startup;
ORA-27102: out of memory
Linux-x86_64 Error: 28: No space left on device
11g RAC error:
SQL> startup;
ORA-00845: MEMORY_TARGET not supported on this system

This section summarizes the configuration of Kernel Parameters for oracle databases in linux.

Linux Kernel Parameters include shared memory, semaphores, network, and open files)
1. Shared Memory

Memory View:
[Root @ oraserv ~] # Free-m
Total used free shared buffers cached
Mem: 249 123 125 0 8 74
-/+ Buffers/cache: 41 208
Swap: 2000 0 2000
Shared Memory is a mechanism used for inter-process communication. Shared memory can be shared by multiple specified processes and is a system resource. Shared Memory is allocated in segments. The maximum and minimum segments are supported.

The shared memory allows two or more processes to access the same memory, just as the malloc () function returns a pointer to the same physical memory area to different processes. When a process changes the content of this address, other processes will notice this change.

The size of all shared memory blocks must be an integer multiple of the system page size. System page size refers to the number of bytes contained in a single memory page in the system. In Linux, the memory page size is 4 kb, but you should still obtain this value (in bytes) by calling getpagesize ).

[Root @ oraserv ~] # Getconf PAGE_SIZE
4096

[Root @ oraserv ~] # Ipcs-l
------ Shared Memory Limits --------
Max number of segments = 4096 // SHMMNI
Max seg size (kbytes) = 4194303 // SHMMAX
Max total shared memory (kbytes) = 1073741824 // SHMALL
Min seg size (bytes) = 1

------ Semaphore Limits --------
Max number of arrays = 128 // SEMMNI
Max semaphores per array = 250 // SEMMSL
Max semaphores system wide = 32000 // SEMMNS
Max ops per semop call = 100 // SEMOPM
Semaphore max value = 32767

------ Messages: Limits --------
Max queues system wide = 16 // MSGMNI
Max size of message (bytes) = 65536 // MSGMAX
Default max size of queue (bytes) = 65536 // MSGMNB

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