Shulou(Shulou.com)06/01 Report--

/ etc/sysctl.conf

Parameter setting explanation

Kernel.shmmni (SHMMNI) 256 *

Kernel.shmmax (SHMMAX)

The minimum required on x86 systems is 268435456 (256MB) and for 64-bit systems, it is 1073741824 (1 GB).

Kernel.shmall (SHMALL) 2 *

SHMALL is set to 8 GB by default (8388608 KB = 8 GB)

If you have more physical memory than this, and it is to be used for the Db2 database system, then this parameter increases to approximately 90% of your computer's physical memory For instance, if you have a computer system with 16 GB of memory to be used primarily for the Db2 database system, then SHMALL should be set to 3774873 (90% of 16 GB is 14.4 GB; 14.4 GB is then divided by 4 KB, which is the base page size). The ipcs output has converted SHMALL into kilobytes. The kernel requires this value as a number of pages.

Kernel.sem (SEMMNI) 256 *

Kernel.sem (SEMMSL) 250

Kernel.sem (SEMMNS) 256000

Kernel.sem (SEMOPM) 32

Kernel.msgmni (MSGMNI) 1024 *

Kernel.msgmax (MSGMAX) 65536

Kernel.msgmnb (MSGMNB) 65536

An example of SEMMNS is the result of SEMMSL multiplied by SEMMNI

# Example for a computer with 32GB of RAM:

Kernel.shmmni=4096

Kernel.shmmax=34359738368

Kernel.shmall=7549746

# kernel.sem=

Kernel.sem=250 1024000 32 4096

Kernel.msgmni=16384

Kernel.msgmax=65536

Kernel.msgmnb=65536

Fs.file-max=65536

Net.ipv4.ip_local_port_range=1024 65000

Net.core.rmem_default=262144

Net.core.rmem_max=262144

Net.core.wmem_default=262144

Net.core.wmem_max=262144

Vm.swappiness=0

How to make parameters take effect by vm.overcommit_memory=0

Run sysctl with-p parameter to load in sysctl settings from the default file / etc/sysctl.conf:

Sysctl-p

To make the changes effective after every reboot:

-SUSE Linux: Make boot.sysctl active.

Su-root

# chkconfig boot.sysctl

Boot.sysctl off

# chkconfig boot.sysctl on

# chkconfig boot.sysctl

Boot.sysctl on

#

-Red Hat: The rc.sysinit initialization script will read the / etc/sysctl.conf file

Automatically.

Check the parameters

# ipcs-l

-Shared Memory Limits-

Max number of segments = 4096 / / SHMMNI

Max seg size (kbytes) = 32768 / / SHMMAX

Max total shared memory (kbytes) = 8388608 / / SHMALL

Min seg size (bytes) = 1

-Semaphore Limits-

Max number of arrays = 1024 / / SEMMNI

Max semaphores per array = 250 / / SEMMSL

Max semaphores system wide = 256000 / / SEMMNS

Max ops per semop call = 32 / / SEMOPM

Semaphore max value = 32767

-Messages: Limits-

Max queues system wide = 1024 / / MSGMNI

Max size of message (bytes) = 65536 / / MSGMAX

Default max size of queue (bytes) = 65536 / / MSGMNB

Another parameter file

/ etc/security/limits.conf

Db2inst1 soft nofile 65536

Db2inst1 hard nofile 65536

Db2inst1 soft nproc 65536

Db2inst1 hard nproc 65536

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