ORA-27125 建库报错，解决方法

oracle 10.2.0.1 Linux_x86_64 在dbca建库时，报错ora-27125错误。

[root@oel ~]# id oracle 
uid=500(oracle) gid=500(oinstall) groups=500(oinstall),501(dba) context=root:system_r:unconfined_t:SystemLow-SystemHigh 
[root@oel ~]# more /proc/sys/vm/hugetlb_shm_group 
0 
[root@oel ~]# echo 501 > /proc/sys/vm/hugetlb_shm_group

将dba组添加到系统内核中，试DBA组的用户有权限使用HugePage。

HugePage的解释如下：

When a process uses some memory, the CPU is marking the RAM as used by that process. For efficiency, the CPU allocate RAM by chunks of4K bytes (it's the default value on many platforms). Those chunks are named pages. Those pages can be swapped to disk, etc.

Since the process address space are virtual, the CPU and the operating system have to remember which page belong to which process, and where it is stored. Obviously, the more pages you have, the more time it takes to find where the memory is mapped. When a process uses 1GB of memory, that's 262144 entries to look up (1GB / 4K). If one Page Table Entry consume 8bytes, that's 2MB (262144 * 8) to look-up.

Most current CPU architectures support bigger pages (so the CPU/OS have less entries to look-up), those are namedHuge pages (on Linux),Super Pages (on BSD) or Large Pages (on Windows), but it all the same thing.

more /proc/meminfo |grep Huge

#可以看到hugepage的信息，一般单块为2MB大小，比4K大多了。