ORA-27125: unable to create shared memory segment

案例环境：

操做系统环境 ： Oracle Linux Server release 5.7 x86_64

数据库版本     ： Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - 64bi

在安装Oracle安装过程当中，dbca 建instance的，遇到以下错误:ORA-27125: unable to create shared memory segment

分析解决：

之前遇到安装ORACLE成功后，启动过程当中遇到ORA-27125错误, 也在博客ORA-27125: unable to create shared memory segment和博客ORA-27125里面记录过，因而按照解决方法作了以下操做:

   1: [root@DB-Server cdrom]# id oracle

   2:  

   3: uid=502(oracle) gid=502(oinstall) groups=502(oinstall),503(dba)

   4:  

   5: [root@DB-Server cdrom]# more /proc/sys/vm/hugetlb_shm_group

   6:  

   7: 0

   8:  

   9: [root@DB-Server cdrom]# echo 502 >/proc/sys/vm/hugetlb_shm_group

  10:  

  11: [root@DB-Server cdrom]# 

而后在/etc/sysctl.conf 里面添加参数vm.hugetlb_shm_group = 502，就能够在下次启动时不报ORA-27125错误。

过后跟老大聊了一下这个错误，老大说他之前也使用这个版本的操做系统和数据库安装镜像（咱们使用一样的操做系统、数据库安装镜像文件），可是没有遇到过这类问题。我也看过eygel的博客http://www.eygle.com/archives/2011/12/hugepageshugetl.html 以及David的博客http://blog.csdn.net/tianlesoftware/article/details/7309046，基本上都是涉及hugetlb_shm_group，通过一番探索，老大发了Metalink上的一个连接给我：https://support.oracle.com/epmos/faces/BugDisplay?_afrLoop=446607573886554&id=4726024&_afrWindowMode=0&_adf.ctrl-state=k6an80rhq_4   以下所示：

Hdr: 4726024 10.2.0.1 RDBMS 10.2.0.1 OSD PRODID-5 PORTID-226 ORA-27125

Abstract: GETTING ORA-27125 WHEN TRYING TO STARTUP INSTANCE

*** 11/08/05 06:47 pm ***

TAR:

----

15683356.6

PROBLEM:

--------

Customer installed 10.2.0.1  on SuSe SLES9

Get the following error when trying to startup instance either using sqlplus or dbca

ORA-27125 unable to create shared memory segment

Linux-86_64 Error: 1 Operation not permitted

DIAGNOSTIC ANALYSIS:

--------------------

Looks like customer is runinng into bug Bug 3681720.  This bug is closed as

dup of 3520770 which indicated problem is fixed in 10.2.

But customer is still encountering this error.

WORKAROUND:

-----------

Set disable_cap_mlock to 1

$ echo 1 > /proc/sys/vm/disable_cap_mlock

RELATED BUGS:

-------------

3681720

3520770

REPRODUCIBILITY:

----------------

TEST CASE:

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STACK TRACE:

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SUPPORTING INFORMATION:

-----------------------

24 HOUR CONTACT INFORMATION FOR P1 BUGS:

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DIAL-IN INFORMATION:

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IMPACT DATE:

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因而我打上10.0.2.4.0的补丁后。而后在/etc/sysctl.conf 将参数vm.hugetlb_shm_group = 502注释后，从新关闭、启动数据库，测试结果显示，ORA-27125错误不见了。显然这是在Linux x86-64平台上，ORACLE 10.2.0.1的一个Bug来的。至于老大为何没有碰到这个错误，他解释是安装完成后，直接打补丁升级，而后启动数据库。可是很奇怪安装过程当中也没有碰到这个错误，而我就屡次碰到了。