Summary of Kernel Parameter settings

Kernel. suid_dumpable = 0
Kernel. sercons_esc =-1
Kernel. sysrq = 0
Kernel. SEM = 250 32000 32 128
Kernel. shmmni = 4096
Kernel. Shmall = 2097152
Kernel. shmmax = 33554432

Kernel. sercons_esc =-1
Kernel. sysrq-timer = 10
Kernel. sysrq-sticky = 0
Kernel. sysrq-Key = 84
Kernel. sysrq = 0
Kernel. SEM = 250 32000 32 128
Kernel. shmmni = 4096
Kernel. Shmall = 2097152
Kernel. shmmax = 33554432

 

/Etc/security/limits. conf
Or ulimit (system-related)
The following are related to databases:
Shmmax-Maximum number of bytes in the shared memory segment. We recommend that you set the value to a greater value than the physical memory size.
Shmmin-minimum size of the shared memory segment.
Shmmni-Maximum number of shared memory segments.
Shmseg-Maximum number of shared memory segments that each process can allocate.
Shmall-the maximum number of concurrent shared memory segments, which is larger than SGA.
Semmns-the maximum number of traffic signals, which depends on the number of processes in Oracle.
Semmsl-the maximum number of signals in each traffic signal set.
Root sysctl-A | grep kernel. s
Sysctl-A | grep fs. File-max
Sysctl-A | grep net. ipv4.ip _ local_port_range
Sysctl-A | grep kernel. shmmax

CAT/proc/sys/kernel/shmmax
************************************
More/CAT/etc/sysctl. conf
Shmmax shared memory segment

Shmmni shared memory identifier count

Shmall maximum allowable memory size

SEM

# Cat/proc/sys/kernel/SEM

250 32000 32 128

250 is the value of semmsl: used to control the maximum number of signals in each signal set.

32000 is the value of semmns, which is used to control the maximum number of signals (rather than signal sets) in the entire Linux system.

32 is the value of semopm: used to control the number of signal operations that can be performed by each semop system call.

128 is the semmni parameter: used to control the maximum number of CITIC number sets in the entire Linux system.

*******************************
Modify Kernel Parameters
[Quote: db788a2c24] # echo "kernel. SEM =/" 250 32000 100 128/">/etc/sysctl. conf
# Echo "kernel. shmmax = 2147483648">/etc/sysctl. conf [/quote: db788a2c24]

In the first command, 250, 32000, and 100 correspond to the four core parameters semmsl, semmns, semopm, and semmni respectively.

 

How to obtain the maximum available memory of JVM

Run the Java-xmxxxxxm-version command on the command line to test the function. Then, the XXXX value is gradually increased. If the execution is normal, the specified memory size is available. Otherwise, the error message is printed.

Set System Parameters
Kernel. shmmax = 536870912
Kernel. shmmni = 4096
Kernel. Shmall = 2097152
Kernel. SEM = 250 32000 100 128
FS. File-max = 65536
Net. ipv4.ip _ local_port_range = 1024 65000

Add the following content to the/etc/security/limits. conf file:
Oracle soft nofile 65536
Oracle hard nofile 65536
Oracle soft nproc 16384
Hard nproc 16384

1.3 HP-UX

1.3.1 Oracle 8

The process is roughly the same as that of unixware. To adjust the kernel parameters, you can use Sam to select/Kernel configuration/actions/apply tuned parameter set/OLTP database server system. In addition, to improve the I/O capability, you also need to adjust the following parameters:

Core parameter reference value explanation

Bufpages 61992 buffer page

Dbc_max_pct 10 maximum percentage of dynamic cache in memory

Dbc_min_pct 10 minimum percentage of dynamic cache in memory

Nbuf

Set the shared library directory shlib_path, not LD_LIBRARY_PATH

Shlib_path = $ shlib_path: $ ORACLE_HOME/LIB; export shlib_path

HP-UX
The default setting seems to be enough for normal installation. In HP-UX 10, the factory default semmns is 128, which may be too small for large database nodes.

You can configure the kernel configurationconfigurable parameters in the System Administration Manager (SAM.