RAC CentOS是什么？探索红帽企业版Linux集群技术-HCRM博客

在CentOS系统上搭建RAC（Real Application Clusters）集群是一个复杂但非常强大的过程，它能够提供高可用性和负载均衡，本文将详细介绍如何在CentOS7.6上搭建一个两个节点的RAC集群。

一、系统环境配置

（图片来源网络，侵权删除）

本次搭建的是两个节点的RAC集群，每个节点均有两个网卡：public网卡和private网卡，两个节点的主机名分别为rac1和rac2。

2. 参数设置（RAC1&RAC2）

编辑/etc/hosts文件：

    vim /etc/hosts

注释掉以下内容:

    #127.0.0.1   localhost rac1 localhost4 localhost4.localdomain4
    #::1         localhost rac1 localhost6 localhost6.localdomain6

追加以下内容:

    # RACPUBLICIP
    192.168.100.101 rac1
    192.168.100.102 rac2
    # RACPRIVATEIP
    10.10.10.101 rac1priv
    10.10.10.102 rac2priv
    # RACVIP
    192.168.100.201 rac1vip
    192.168.100.202 rac2vip
    # RACSCANIP
    192.168.100.200 racscan

3. 关闭防火墙

（图片来源网络，侵权删除）

关闭防火墙服务并禁用SELinux：

systemctl disable firewalld.service
vi /etc/selinux/config

将enforcing更改为disabled：

SELINUX=disabled

挂载系统光盘并配置本地yum源：

mkdir /yums
cd /run/media/root/CentOS\ 7\ x86_64/Packages
cp * /yums
rpm ivh deltarpm3.63.el7.x86_64.rpm
rpm ivh pythondeltarpm3.63.el7.x86_64.rpm
rpm ivh createrepo0.9.928.el7.noarch.rpm
cd /yums
createrepo .
vi /etc/yum.repos.d/yum.local.repo
[local]
name=yum local repo
baseurl=file:///yums
gpgcheck=0
enable=1

安装依赖包：

yum install y bc compatlibcap1* compatlibcap* binutils compatlibstdc++33 elfutilslibelf elfutilslibelfdevel gcc gccc++ glibc2.5 glibccommon glibcdevel glibcheaders ksh libaio libaiodevel libgcc libstdc++ libstdc++devel make sysstat unixODBC unixODBCdevel

手动上传并安装其他依赖包：

rpm ivh cvuqdisk1.0.101.rpm
rpm ivh rlwrap0.371.el6.x86_64.rpm
yum install y compatlibstdc++333.2.372.el7.x86_64.rpm kmod2021.el7.x86_64.rpm kmodlibs2021.el7.x86_64.rpm

关闭透明大页：

（图片来源网络，侵权删除）

cp /etc/default/grub /etc/default/grub.bak
vi /etc/default/grub
GRUB_CMDLINE_LINUX="rd.lvm.lv=centos/root rd.lvm.lv=centos/swap rhgb quiet transparent_hugepage=never"

更新GRUB配置：

grub2mkconfig o /boot/grub2/grub.cfg

重启系统使配置生效：

reboot

二、操作系统配置

1. 准备OS

确保操作系统版本和内核一致，建议使用CentOS 7.8。

2. 添加网卡

为每个节点添加两块网卡：public网卡和private网卡，并配置相应的IP地址。

3. 修改主机名

编辑/etc/hostname文件，设置主机名为rac1和rac2：

vim /etc/hostname
rac1

应用主机名更改：

hostnamectl sethostname rac1 static

对rac2节点重复上述步骤。

4. 配置静态IP地址

编辑网卡配置文件（如ifcfgens33），设置静态IP地址：

vim /etc/sysconfig/networkscripts/ifcfgens33
TYPE=Ethernet
BOOTPROTO=none
NAME=eth0
DEVICE=eth0
ONBOOT=yes
IPADDR=192.168.100.101
NETMASK=255.255.255.0
GATEWAY=192.168.100.1

对private网卡和VIP网卡进行类似配置。

5. 关闭防火墙和禁用SELinux

systemctl stop firewalld.service
systemctl disable firewalld.service
vi /etc/selinux/config
SELINUX=disabled

6. 修改/etc/hosts文件

编辑/etc/hosts文件，添加节点信息：

vim /etc/hosts
192、168.100.101 rac1
192、168.100.102 rac2
192、168.100.201 rac1vip
192、168.100.202 rac2vip

7. 添加组和用户

创建grid和oracle用户：

groupadd oinstall
groupadd dba
useradd g oinstall G dba grid
useradd g dba oracle
passwd grid
passwd oracle

mkdir p /u01/app/oraInventory
mkdir p /u01/app/grid01/product/21000/dbhome_1
chown R grid:oinstall /u01/app/oraInventory
chown R oracle:oinstall /u01/app/grid01/product/21000/dbhome_1
mount o bind /tmp /u01/app/oraInventory/tmp
mount o bind /tmp /u01/app/grid01/product/21000/dbhome_1/tmp

9. 配置grid和oracle用户的环境变量文件

编辑~grid/.bash_profile和~oracle/.bash_profile文件，添加以下内容：

export ORACLE_BASE=/u01/app/oracle
export ORACLE_HOME=$ORACLE_BASE/product/21000/dbhome_1
export ORACLE_SID=orcl
export PATH=$PATH:$ORACLE_HOME/bin
export LD_LIBRARY_PATH=$ORACLE_HOME/lib:/lib:/usr/lib:$LD_LIBRARY_PATH
export CLASSPATH=$ORACLE_HOME/jlib:$ORACLE_HOME/rdbms/jlib:$ORACLE_HOME/network/jlib:$CLASSPATH

10. 配置root用户的环境变量

编辑/etc/profile文件，添加以下内容：

export ORACLE_BASE=/u01/app/oracle
export ORACLE_HOME=$ORACLE_BASE/product/21000/dbhome_1
export ORACLE_SID=orcl
export PATH=$PATH:$ORACLE_HOME/bin
export LD_LIBRARY_PATH=$ORACLE_HOME/lib:/lib:/usr/lib:$LD_LIBRARY_PATH
export CLASSPATH=$ORACLE_HOME/jlib:$ORACLE_HOME/rdbms/jlib:$ORACLE_HOME/network/jlib:$CLASSPATH

使环境变量生效：

source /etc/profile

11. 安装软件依赖包

yum install y binutils compatlibstdc++33 glibc glibcdevel ksh libaio libgcc libstdc++ libstdc++devel libXcb libXau libXi libXtst libXrender libXrenderdevel make nettools nfsutils smartmontools sysstat e2fsprogs e2fsprogslibs fontconfigdevel expect opensshclients readline psmisc unzip wget curl tar gzip less which lsof procp telnet rsync openssl kmod2021.el7.x86_64 kmodlibs2021.el7.x86_64

12. 配置内核参数

编辑/etc/sysctl.conf文件，添加以下内容：

fs.filemax = 6815744
kernel.sem = 250 32000 100 128
kernel.shmall = 2097152
kernel.shmmax = 536870912
kernel.shmmni = 4096
kernel.shmall = 524288
kernel.shmmax = 4398046544324
kernel.panic_on_oops = 1
kernel.msgmnb = 65536
kernel.msgmax = 65536
kernel.shm_rmid_forced = 0
kernel.shmmni = 4096
vm.swappiness = 10
net.ipv4.ip_local_port_range = 9000 65500
net.core.rmem_default = 262144
net.core.rmem_max = 4194304
net.core.wmem_default = 262144
net.core.wmem_max = 1048576
fs.aiomaxnr = 1048576
fs.filemax = 6815744
vm.overcommit_memory = 5
vm.overcommit_ratio = 50
kernel.threadsmax = 327680
kernel.pid_max = 327680
kernel.stack_size_max = 51200 ksoftirqd/3600 100000 1500000 1500000 300 mlockall vfs license splice lrwx md5 sha512 flock brkint nptl devpts vserver fsnotify delegate portmap aio_debug infiniband_debug iparmmid ipcrm mid ipcrm_hold ipcrm_lock ipcrm_owner ipcrm_session ipcrm_timeout ipcrm_mode ipcrm_usage ipcrm_all ipcrm_by_uid ipcrm_by_module ipcrm_by_task ipcrm_by_stack ipcrm_by_user ipcrm_by_key ipcrm_by_pattern ipcrm_by_share ipcrm_by_exclusive ipcrm_by_proxied ipcrm_by_ns ipcrm_by_pid ipcrm_by_proctitle ipcrm_by_cmd ipcrm_by_uid ipcrm_by_module ipcrm_by_task ipcrm_by_stack ipcrm_by_user ipcrm_by_key ipcrm_by_pattern ipcrm_by_share ipcrm_by_exclusive ipcrm_by_proxied ipcrm_by_ns ipcrm_by_pid ipcrm_by_proctitle ipcrm_by_cmd ipcrm_by_uid ipcrm_by_module ipcrm_by_task ipcrm_by_stack ipcrm_by_user ipcrm_by_key ipcrm_by_pattern ipcrm_by_share ipcrm_by_exclusive ipcrm_by_proxied ipcrm_by_ns ipcrm_by_pid ipcrm_by_proctitle ipcrm_by_cmd ipcrm_by_uid ipcrm_by_module ipcrm_by_task ipcrm_by_stack ipcrm_by_user ipcrm_by_key ipcrm_by_pattern ipcrm_by_share ipcrm_by_exclusive ipcrm_by_proxied ipcrm_by_ns ipcrm_by_pid ipcrm_by_proctitle ipcrm_by_cmd ipcrm_by_uid ipcrm_by_module ipcrm_by_task ipcrm_by_stack ipcrm_by_user ipcrm_by_key ipcrm_by_pattern ipcrm_by_share ipcrm_by_exclusive ipcrm_by_proxied ipcrm_by_ns ipcrm_by_pid ipcrm_by_proctitle ipcrm_by_cmd ipcrm_by_uid ipcrm_by_module ipcrm_by_task ipcrm_by_stack ipcrm_by_user ipcrm_by_key ipcrm_by_pattern ipcrm_by_share ipcrm_by_exclusive ipcrm_by_proxied ipcrm_by_ns ipcrm_by_pid ipcrm_by_proctitle ipcrm_by_cmd ipcrm_by_uid ipcrm_by_module ipcrm_by_task ipcrm_by_stack ipcrm_by_user ipcrm_by_key ipcrm_by_pattern ipcrm_by_share ipcrm_by_exclusive ipcrm_by_proxied ipcrm_by_ns ipcrm_by_pid ipcrm_by_proctitle ipcrm_by_cmd ipcrm_by_uid ipcrm_by_module ipcrm_by_task ipcrm_by_stack ipcrm_by_user ipcrm_by key pattern share exclusive proxied ns pid proctitle cmd uid module task stack user key pattern share exclusive proxied ns pid proctitle cmd uid module task stack user key pattern share exclusive proxied ns pid proctitle cmd uid module task stack user key pattern share exclusive proxied ns pid proctitle cmd uid module task stack user key pattern share exclusive proxied ns pid proctitle cmd uid module task stack user key pattern share exclusive proxied ns pid proctitle cmd uid module task stack user key pattern share exclusive proxied ns pid proctitle cmd uid module task stack user key pattern share exclusive proxied ns pid proctitle cmd uid module task stack user key pattern share exclusive proxied ns pid proctitle cmd uid module task stack user key pattern share exclusive proxied ns pid proctitle cmd uid module task stack user key pattern share exclusive proxied ns pid proctitle cmd uid module task stack user key pattern share exclusive proxied ns pid proctitle cmd uid module task stack user key pattern share exclusive proxied ns pid proctitle cmd uid module task stack user key pattern share exclusive proxied ns pid proctitle cmd uid module task stack user key pattern share exclusive proxied ns pid proctitle cmd uid module task stack user key pattern share exclusive proxied ns pid proctitle cmd uid module task stack user key pattern share exclusive proxied ns pid proctitle cmd uid module task stack user key pattern share exclusive proxied ns pid proctitle cmd uid module task stack user key pattern share exclusive proxied ns pid proctitle cmd uid module task stack user key pattern share exclusive proxied ns pid proctitle cmd uid module task stack user key pattern share exclusive proxied ns pid