在大内存的服务器上部署 Oracle 时都需要配置 hugepage，配置后，可以通过/proc/meminfo 确认大页的生效情况，如下：http://www.cndba.cn/dave/article/131568

$ grep HugePages /proc/meminfo
AnonHugePages:         0 kB
HugePages_Total:   61461
HugePages_Free:    61461
HugePages_Rsvd:        0
HugePages_Surp:        0

也可以通过数据库的 alert log 日志确认大页的信息，比如在 11g 的 alert log 中会显示如下信息：

Tue Feb 10 15:40:58 2015
Starting ORACLE instance (normal)
************************ Large Pages Information *******************
Per process system memlock (soft) limit = 48 GB

Total Shared Global Region in Large Pages = 1026 MB (100%)

Large Pages used by this instance: 513 (1026 MB)
Large Pages unused system wide = 1 (2048 KB)
Large Pages configured system wide = 514 (1028 MB)
Large Page size = 2048 KB
********************************************************************

但是在 Oracle 12c 之后的版本，大页的信息有改变，如下：http://www.cndba.cn/dave/article/131568

**********************************************************************
Tue Feb 10 15:26:02 2015
Dump of system resources acquired for SHARED GLOBAL AREA (SGA)

Tue Feb 10 15:26:02 2015
 Per process system memlock (soft) limit = 48G
Tue Feb 10 15:26:02 2015
 Expected per process system memlock (soft) limit to lock
 SHARED GLOBAL AREA (SGA) into memory: 1026M
Tue Feb 10 15:26:02 2015
 Available system pagesizes:
  4K, 2048K
Tue Feb 10 15:26:02 2015
 Supported system pagesize(s):
Tue Feb 10 15:26:02 2015
  PAGESIZE  AVAILABLE_PAGES  EXPECTED_PAGES  ALLOCATED_PAGES  ERROR(s)
Tue Feb 10 15:26:02 2015
        4K       Configured               5               5        NONE
Tue Feb 10 15:26:02 2015
     2048K              514             513             513        NONE
Tue Feb 10 15:26:02 2015
**********************************************************************

如果大页的信息配置的不正确，也会给到提示信息，从而辅助我们进行修复：

**********************************************************************
2024-06-17T20:18:11.205055+08:00
Dump of system resources acquired for SHARED GLOBAL AREA (SGA) 

2024-06-17T20:18:11.205120+08:00
 Per process system memlock (soft) limit = 64K
2024-06-17T20:18:11.205156+08:00
 Expected per process system memlock (soft) limit to lock
 SHARED GLOBAL AREA (SGA) into memory: 120G
2024-06-17T20:18:11.205228+08:00
 Available system pagesizes:
  4K, 2048K 
2024-06-17T20:18:11.205295+08:00
 Supported system pagesize(s):
2024-06-17T20:18:11.205329+08:00
  PAGESIZE  AVAILABLE_PAGES  EXPECTED_PAGES  ALLOCATED_PAGES  ERROR(s)
2024-06-17T20:18:11.205365+08:00
        4K       Configured               9        31457289        NONE
2024-06-17T20:18:11.205434+08:00
     2048K            61461           61441               0        NONE
2024-06-17T20:18:11.205469+08:00
RECOMMENDATION:
2024-06-17T20:18:11.205504+08:00
 1. Increase per process memlock (soft) limit to at least 120GB
 to lock 100% of SHARED GLOBAL AREA (SGA) pages into physical memory
2024-06-17T20:18:11.205571+08:00

比如我们这里就是因为/etc/security/limits.conf 没有配置正确导致大页异常，没有使用，所以最开始HugePages_Total = HugePages_Free。

Large Pages Information in the Alert Log (Doc ID 1392543.1)
Large Pages Information had been changed in the Oracle Database 12c Alert Log (Doc ID 1969379.1)http://www.cndba.cn/dave/article/131568

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