環境檢查
數據庫內存超過4G時，使用dbca建庫默認選項AMM是關閉的，內存超過8G時，oracle推薦使用hugepages，它可以將部分數據鎖定在內存中，處理效率比較高、性能好。
確認服務器物理內存已經超過8G，是大內存
確認數據庫實例沒有使用AMM，hugepages與AMM不同時使用
Memlock
如果/etc/security/limits.d/*.conf中沒有關於memlock參數的設置，那么
memlock的值介於SGA與物理內存之間，比SGA大，比物理內存小
推薦值SGA+PGA為物理內存80%，memlock為物理內存90%
Memlock = 物理內存*90%*1024*1024
vim /etc/security/limits.conf
oracle soft memlock 237363200
oracle hard memlock 237363200
# su - oracle
$ ulimit -l
237363200
腳本獲取推薦值
chmod +x hugepages_settings.sh
[root@crcsn1 scripts]# ./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 = 72708
[root@crcsn1 scripts]# ipcs -m
------ Shared Memory Segments --------
key shmid owner perms bytes nattch status
0x00000000 1245184 grid 600 4096 0
0x00000000 1277953 grid 600 4096 0
0x4dfc72ac 1310722 grid 600 24576 48
0x00000000 1343491 grid 600 8802304 124
0x00000000 1376260 grid 600 1056964608 62
0x00000000 1409029 grid 600 7974912 62
0xef940690 1441798 grid 600 20480 62
0x00000000 2129927 oracle 600 30035968 614
0x00000000 2162696 oracle 600 150860726272 307
0x00000000 2195465 oracle 600 506834944 307
0x51c60604 2228234 oracle 600 24576 307
設置hugepages
# vim /etc/sysctl.conf
vm.nr_hugepages = 72708
# sysctl -p
# grep HugePages /proc/meminfo
AnonHugePages: 1093632 kB
HugePages_Total: 61313
HugePages_Free: 61313
HugePages_Rsvd: 0
HugePages_Surp: 0
附件
hugepages_settings.sh
| #!/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); }'` ...skipping... 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 |
參考
- HugePages on Oracle Linux 64-bit (文檔 ID 361468.1)
- Oracle Linux: Shell Script to Calculate Values Recommended Linux HugePages / HugeTLB Configuration (文檔 ID 401749.1)