Kernel Parameters during Oracle Installation

Name	Description	Reasonable values
shmmax	maximum size of shared memory segment (bytes)	250kb + 8.2kb * shared_buffers + 14.2kb * max_connections or infinity
shmmin	minimum size of shared memory segment (bytes)	1
Shmall	total amount of shared memory available (bytes or pages)	If bytes, same as shmmax ; If pages, Ceil (shmmax/page_size)
shmseg	maximum number of shared memory segments per Process	only 1 segment is needed, but the default is much higher
shmmni	maximum number of shared memory segments system-wide	like shmseg plus room for other applications
semmni	maximum number of semaphore Identifiers (that is, sets)	= Ceil (max_connections/16)
semmns	maximum number of semaphores system-wide	Ceil (max_connections/16) * 17 + room for other applications
semmsl	maximum number of semaphores per set	>= 17
semmap	Number of entries in semaphore Map	See text
Semvmx	Maximum Value of semaphore	> = 255 (the default is often 32767, do not change unless asked .)

Therefore, the meaning of the three parameters configured during Oracle Installation on Linux is very clear. For example:

Kernel. Shmall = 2097152 ------Total available shared memory, Unit page, on the 32-bit system Previous Page = 4 K, that is, 4096 bytes. Set 2097152*4 K/1024/1024 = 8 GB, that is, the shared memory is 8 GB in total.
Kernel. shmmax = 2147483648 ----- maximum number of single shared memory segments, 2147483648/1024/1024 = 2048 m = 2G
Kernel. shmmni = 4096 ------- minimum value of a single shared memory segment 1096b = 4 K

 

Kernel. shmmax = 268435456

Kernel. shmmni = 4096

Kernel. Shmall = 2097152

Kernel. SEM = 250 32000 100 128

FS. File-max = 65536

Net. ipv4.ip _ local_port_range = 1024 65000

 

Modify/Etc/sysctl. confFile. The meanings of several parameters are as follows:

Kernel. shmmaxIndicates the maximum shared memory. If it is small, it can be determined based on the actual situation. Generally, it is half of the physical memory, but my VM only has256 mSo it's all included.

ShmmniIndicates that the minimum shared memory is fixed.4096kb

ShmallMemory size

SEM 4Parameters areSemmsl: Each user has the maximum number of semaphores,Semmns: Maximum number of system semaphores,Semopm: Each timeSemopmSystem Call operations,Semmni: The maximum number of hard data sets. This4Parameters are fixed content size.

File-maxFixed size65536

Ip_local_port_rangeIndicates the port range, which is the specified content.