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/etc/sysctl.conf
参数设置讲解
kernel.shmmni (SHMMNI) 256 *
kernel.shmmax (SHMMAX)
the minimum required on x86 systems is 268435456 (256 MB) 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
SEMMNS is the result of SEMMSL multiplied by SEMMNI
举例
#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
vm.overcommit_memory=0
如何使得参数生效
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.
查看一下参数
# 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
另外一个参数文件
/etc/security/limits.conf
db2inst1 soft nofile 65536
db2inst1 hard nofile 65536
db2inst1 soft nproc 65536
db2inst1 hard nproc 65536
