Huges_Pages Setup for Host

Find the memory on the host:

[gg60@ut03 :+ASM] /home/dba/gg60 $ free -m

total used free shared buffers cached

Mem: 3820 3773 47 0 396 2045

[gg60@ut03 :+ASM] /home/dba/gg60 $ cat /proc/meminfo | grep Mem

MemTotal: 3912580 kB

MemFree: 64228 kB

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Set the value for vm.nr_hugepages:

3820/1024 = 3.73 GB

1.5 GB is 40% (this will be the sga_target value 1528 MB )

(1.50 * 1024 * 1024/2048) + 5 = 773

vm.nr_hugepages=773

A) Edit /etc/sysctl.conf

Add line:

vm.nr_hugepages=773

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Set the value for Soft memlock and Hard memlock:

3912580 * 2 = 7825160

B) Edit: /etc/security/limits.conf

Add lines:

oracle soft memlock 7825160

oracle hard memlock 7825160

*************************************************************************************

.75 * 3264 * 1024 * 1024 = 3004170240

kernel.shmmax = 3004170240

C) Edit /etc/sysctl.conf

Add line:

kernel.shmmax = 3004170240

*********************************************************************************

Open SRQ for Unix Admin to make settings (A, B, C) then bounce host.

*********************************************************************************

DBA modify init.ora file in this location: /opt/oracle/duoxxxa/admin/scripts/initduoxxxa.ora’

Add lines:

sga_target=1528M

use_large_pages=’ONLY’

Take out lines:

memory_max_target

memory_target

pga_aggregate_target

Then rename the pfile and spfile (ie, *.old) in: /opt/oracle/product/11.2.0.4/dbs

Then bounce the database as follows:

sqlplus ‘ /as sysdba’ > shutdown immediate;

startup pfile=’/opt/oracle/duoxxxa/admin/scripts/initduoxxxa.ora’

create spfile from pfile=’/opt/oracle/duoxxxa/admin/scripts/initduoxxxa.ora’

shutdown immediate;

Type: ASM

srvctl start database –d duoxxxa

In another session, tail the errorlog:

tail -f /opt/oracle/diag/rdbms/duoxxxa/duoxxxa/trace/alert_duoxxa.log

Verify that it it using huge pages. It will mention it in the alert log.

Appendix A:

Excerpt from document Oracle 11gR2 Application Database Project Procedures

UNIX ADMIN PART:

HUGE PAGE Settings**

Edit the /etc/sysctl.conf and add vm.nr_hugepages=xxxx
Edit the /etc/security/limits.conf

Soft memlock xxxxxxxx

Hard memlock xxxxxxxx

Edit the /etc/sysctl.conf kernel.shmmax= xxxxxxxxxx

Edit the /etc/sysctl.conf and add vm.nr_hugepages=xxxx
Edit the /etc/security/limits.conf

Soft memlock xxxxxxxx

Hard memlock xxxxxxxx

Edit the /etc/sysctl.conf kernel.shmmax= xxxxxxxxxx
How to determine the value for vm.nr_hugepages

CPU and Memory configuration details will get change based on the database size.

Example:-

	Small Size DB	Medium Size DB	Large Size DB
CPU	2	4	8+
RAM Memory	4 GB	8 GB	16 GB+

Set exactly 40% of physical RAM Memory to the Database SGA Memory.

Example:-if RAM Memory is 4 GB, then 40% should be allocate to SGA. SGA should be 1.6 GB.

If you need 1.6GB for the SGA,

Soundar Mahendran