[20190523]修改参数后一些细节注意.txt
--//昨天远程给别人解决一个小问题,就是配置使用hugepage.一些细节必须注意,通过例子说明问题.
1.环境:
# cat /proc/version
Linux version 2.6.32-220.el6.x86_64 (mockbuild@c6b18n3.bsys.dev.centos.org) (gcc version 4.4.6 20110731 (Red Hat 4.4.6-3) (GCC) ) #1 SMP Tue Dec 6 19:48:22 GMT 2011
2.配置hugepages要修改/etc/security/limits.conf,加入如下注解部分:
# grep memlock /etc/security/limits.conf
# - memlock - max locked-in-memory address space (KB)
#* soft memlock 53248000
#* hard memlock 53248000
--//当前是没有打开.相当于修改配置文件.登录oracle用户:
$ ps -ef | grep bas[h] | grep oracl[e]
oracle 25704 25703 5 10:38 pts/0 00:00:00 -bash
--//bash进程号=25704
$ cat /proc/25704/limits
Limit Soft Limit Hard Limit Units
Max cpu time unlimited unlimited seconds
Max file size unlimited unlimited bytes
Max data size unlimited unlimited bytes
Max stack size 10485760 unlimited bytes
Max core file size 0 unlimited bytes
Max resident set unlimited unlimited bytes
Max processes 16384 16384 processes
Max open files 65536 65536 files
Max locked memory 65536 65536 bytes
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Max address space unlimited unlimited bytes
Max file locks unlimited unlimited locks
Max pending signals 30408 30408 signals
Max msgqueue size 819200 819200 bytes
Max nice priority 0 0
Max realtime priority 0 0
Max realtime timeout unlimited unlimited us
--//如果你在别的窗口修改/etc/security/limits.conf:
* soft memlock 53248000
* hard memlock 53248000
--//进程号=25704配置并不会改变,也就是要退出再登录才生效,这样情况下使用这个环境启动数据库肯定无法启动.
--//在登录1个窗口:
$ ps -ef | grep bas[h] | grep oracl[e]
oracle 25704 25703 0 10:38 pts/0 00:00:00 -bash
oracle 25844 25842 7 10:42 pts/1 00:00:00 -bash
--//新增加1个窗口,进程号=25844
$ cat /proc/25844/limits
Limit Soft Limit Hard Limit Units
Max cpu time unlimited unlimited seconds
Max file size unlimited unlimited bytes
Max data size unlimited unlimited bytes
Max stack size 10485760 unlimited bytes
Max core file size 0 unlimited bytes
Max resident set unlimited unlimited bytes
Max processes 16384 16384 processes
Max open files 65536 65536 files
Max locked memory 54525952000 54525952000 bytes
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Max address space unlimited unlimited bytes
Max file locks unlimited unlimited locks
Max pending signals 30408 30408 signals
Max msgqueue size 819200 819200 bytes
Max nice priority 0 0
Max realtime priority 0 0
Max realtime timeout unlimited unlimited us
--//注意看下划线. 54525952000/1024 = 53248000 KB.
--//也就是一些细节在工作中一定要注意.