hugepage设置

1.设置memlock

编辑/etc/security/limits.conf

增加：

* Soft memlock 稍小于RAM值
* hard memlock 稍小于RAM值

验证

ulimit -l
104857600   --- 为memlock大小

2.禁用AMM特性

SQL> show parameter target

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
archive_lag_target                   integer     0
db_flashback_retention_target        integer     1440
fast_start_io_target                 integer     0
fast_start_mttr_target               integer     0
memory_max_target                    big integer 0
memory_target                        big integer 0
parallel_servers_target              integer     16
pga_aggregate_target                 big integer 200M
sga_target                           big integer 600M
SQL>

3.根据Oracle的脚本计算hugepage大小（计算时要确保Oracle已经启动）

./hugepages_setting.sh

4.根据脚本的计算值在2个节点编辑/etc/sysctl.conf

加入

vm.nr_hugepages = 30739

5.设置USE_LARGE_PAGES

ALTER SYSTEM SET use_large_pages=only SCOPE=SPFILE;
SHUTDOWN IMMEDIATE;
STARTUP;

alert日志显示

****************** Large Pages Information *****************

Total Shared Global Region in Large Pages = 602 MB (100%)

Large Pages used by this instance: 301 (602 MB)
Large Pages unused system wide = 5 (10 MB) (alloc incr 4096 KB)
Large Pages configured system wide = 306 (612 MB)
Large Page size = 2048 KB
***********************************************************

6.查看

# grep HugePages /proc/meminfo
HugePages_Total:    1496
HugePages_Free:      485
HugePages_Rsvd:      446
HugePages_Surp:        0

上面的输出会发生变化，确保配置有效，the HugePages_Free value should be smaller than HugePages_Total and there should be some HugePages_Rsv.

7.禁用透明大页

（1）查看是否开启

# cat /sys/kernel/mm/transparent_hugepage/enabled
[always] madvise never
#

[always]表示启用

[never]表示禁用

# grep AnonHugePages /proc/meminfo
AnonHugePages:  20142080 kB

:heart:（2）和（3）两种方法，优先选择（2）

（2）修改文件/etc/grub.conf,添加一行：

transparent_hugepage=never

（3）修改文件/etc/rc.local文件，添加：

if test -f /sys/kernel/mm/transparent_hugepage/enabled; then
echo never > /sys/kernel/mm/transparent_hugepage/enabled
fi
if test -f /sys/kernel/mm/transparent_hugepage/defrag; then
echo never > /sys/kernel/mm/transparent_hugepage/defrag
fi

（4）重启

参考：

来自为知笔记(Wiz)