環境:
OS:Centos 7
DB:11.2.0.4
1.查看系統當前的大頁使用情況:
[root@localhost ~]# cat /proc/meminfo |grep Huge
HugePages_Total: 0
HugePages_Free: 0
HugePages_Rsvd: 0
HugePages_Surp: 0
Hugepagesize: 2048 kB --大頁大小是2M
2.查看sga大小
SQL> show parameter sga_max
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
sga_max_size big integer 3568M
3.設置大頁的數量
--這里是 1800 個*2M=3600M,SGA最大3568M,大頁的內存要大於SGA大小,才能被ORACLE使用,所以我設置1800個.
可以允許如下腳本讓其給出建議值:
#!/bin/bash # # hugepages_settings.sh # # Linux bash script to compute values for the # recommended HugePages/HugeTLB configuration # on Oracle Linux # # Note: This script does calculation for all shared memory # segments available when the script is run, no matter it # is an Oracle RDBMS shared memory segment or not. # # This script is provided by Doc ID 401749.1 from My Oracle Support # http://support.oracle.com
# Welcome text echo " This script is provided by Doc ID 401749.1 from My Oracle Support (http://support.oracle.com) where it is intended to compute values for
the recommended HugePages/HugeTLB configuration for the current shared memory segments on Oracle Linux. Before proceeding with the execution please note following: * For ASM instance, it needs to configure ASMM instead of AMM. * The 'pga_aggregate_target' is outside the SGA and you should accommodate this while calculating SGA size. * In case you changes the DB SGA size, as the new SGA will not fit in the previous HugePages configuration, it had better disable the whole HugePages, start the DB with new SGA size and run the script again. And make sure that: * Oracle Database instance(s) are up and running * Oracle Database 11g Automatic Memory Management (AMM) is not setup (See Doc ID 749851.1) * The shared memory segments can be listed by command: # ipcs -m Press Enter to proceed..." read # Check for the kernel version KERN=`uname -r | awk -F. '{ printf("%d.%d\n",$1,$2); }'` # Find out the HugePage size HPG_SZ=`grep Hugepagesize /proc/meminfo | awk '{print $2}'` if [ -z "$HPG_SZ" ];then echo "The hugepages may not be supported in the system where the script is being executed." exit 1 fi # Initialize the counter NUM_PG=0 # Cumulative number of pages required to handle the running shared memory segments for SEG_BYTES in `ipcs -m | cut -c44-300 | awk '{print $1}' | grep "[0-9][0-9]*"` do MIN_PG=`echo "$SEG_BYTES/($HPG_SZ*1024)" | bc -q` if [ $MIN_PG -gt 0 ]; then NUM_PG=`echo "$NUM_PG+$MIN_PG+1" | bc -q` fi done RES_BYTES=`echo "$NUM_PG * $HPG_SZ * 1024" | bc -q` # An SGA less than 100MB does not make sense # Bail out if that is the case
if [ $RES_BYTES -lt 100000000 ]; then echo "***********" echo "** ERROR **" echo "***********" echo "Sorry! There are not enough total of shared memory segments allocated for
HugePages configuration. HugePages can only be used for shared memory segments that you can list by command: # ipcs -m of a size that can match an Oracle Database SGA. Please make sure that: * Oracle Database instance is up and running * Oracle Database 11g Automatic Memory Management (AMM) is not configured" exit 1 fi # Finish with results case $KERN in
'2.2') echo "Kernel version $KERN is not supported. Exiting." ;; '2.4') HUGETLB_POOL=`echo "$NUM_PG*$HPG_SZ/1024" | bc -q`; echo "Recommended setting: vm.hugetlb_pool = $HUGETLB_POOL" ;; '2.6') echo "Recommended setting: vm.nr_hugepages = $NUM_PG" ;; '3.8') echo "Recommended setting: vm.nr_hugepages = $NUM_PG" ;; '3.10') echo "Recommended setting: vm.nr_hugepages = $NUM_PG" ;; '4.1') echo "Recommended setting: vm.nr_hugepages = $NUM_PG" ;; esac # End
[root@localhost tmp]# ./hugepages_settings.sh This script is provided by Doc ID 401749.1 from My Oracle Support (http://support.oracle.com) where it is intended to compute values for
the recommended HugePages/HugeTLB configuration for the current shared memory segments on Oracle Linux. Before proceeding with the execution please note following: * For ASM instance, it needs to configure ASMM instead of AMM. * The 'pga_aggregate_target' is outside the SGA and you should accommodate this while calculating SGA size. * In case you changes the DB SGA size, as the new SGA will not fit in the previous HugePages configuration, it had better disable the whole HugePages, start the DB with new SGA size and run the script again. And make sure that: * Oracle Database instance(s) are up and running * Oracle Database 11g Automatic Memory Management (AMM) is not setup (See Doc ID 749851.1) * The shared memory segments can be listed by command: # ipcs -m Press Enter to proceed... Recommended setting: vm.nr_hugepages = 1789
vi /etc/sysctl.conf
在里面增加一行:
vm.nr_hugepages=1800
保存之后執行:
sysctl -p
查看:--如果HugePages_Free:未到1800,不停的執行sysctl -p,使HugePages_Total達到設置的值
[root@localhost ~]# cat /proc/meminfo |grep Huge
HugePages_Total: 1800
HugePages_Free: 1800
HugePages_Rsvd: 0
HugePages_Surp: 0
Hugepagesize: 2048 kB
我這里寫個使用crontab里執行
[root@localhost tmp]# more flush_huge.sh
#!/bin/bash
. /etc/profile
. ~/.bash_profile
sysctl -p
crontab里做的配置
* * * * * /tmp/flush_huge.sh
* * * * * sleep 10; /tmp/flush_huge.sh
* * * * * sleep 20; /tmp/flush_huge.sh
* * * * * sleep 30; /tmp/flush_huge.sh
* * * * * sleep 40; /tmp/flush_huge.sh
* * * * * sleep 50; /tmp/flush_huge.sh
4.還需要設置內存鎖:
--此設置需要重新登陸或重啟才能生效, memlock數量要大於大頁的數量--設置為-1,不限制。
vi /etc/security/limits.conf
oracle soft memlock -1
oracle hard memlock -1
[root@bys3 ~]#ulimit -l
3500000 -----這個數字就是針對大頁數量的限制的,足夠用。
5.重啟數據庫,大頁已經被ORACLE用上了。
SYS@ bys3>shutdown immediate;
SYS@ bys3>startup
重啟數據庫過程中不斷執行,cat /proc/meminfo |grep Huge,能看到HugePages_Free:的數量不斷減少,說明大頁正在被使用。
[root@bys3 ~]# cat /proc/meminfo |grep Huge
HugePages_Total: 1800
HugePages_Free: 1701
HugePages_Rsvd: 10
HugePages_Surp: 0
Hugepagesize: 2048 kB
-- The End --