前言* DRBD(DistributedReplicatedBlockDevice)是一個基于塊設(shè)備級別在遠(yuǎn)程服務(wù)器直接同步和鏡像數(shù)據(jù)的開源軟件，類似于RAID1數(shù)據(jù)鏡像，通常配合keepalived、heartbeat等HA軟件來實(shí)現(xiàn)高可用性。這里簡單記錄僅供參考。

一、實(shí)施環(huán)境

系統(tǒng)版本：CentOS 5.8
DRBD版本: drbd-8.3.15
Keepalived：keepalived-1.1.15
Master：192.168.149.128
Backup：192.168.149.129

二、初始化配置

1)   在128、129兩臺服務(wù)器/etc/hosts里面都添加如下配置：

192.168.149.128  node1
192.168.149.129  node2

2)   優(yōu)化系統(tǒng)kernel參數(shù)，直接上sysctl.conf配置如下:

net.ipv4.ip_forward = 0
net.ipv4.conf.default.rp_filter = 1
net.ipv4.conf.default.accept_source_route = 0
kernel.sysrq = 0
kernel.core_uses_pid = 1
net.ipv4.tcp_syncookies = 1
kernel.msgmnb = 65536
kernel.msgmax = 65536
kernel.shmmax = 68719476736
kernel.shmall = 4294967296
net.ipv4.tcp_max_tw_buckets = 10000
net.ipv4.tcp_sack = 1
net.ipv4.tcp_window_scaling = 1
net.ipv4.tcp_rmem = 4096        87380   4194304
net.ipv4.tcp_wmem = 4096        16384   4194304
net.core.wmem_default = 8388608
net.core.rmem_default = 8388608
net.core.rmem_max = 16777216
net.core.wmem_max = 16777216
net.core.netdev_max_backlog = 262144
net.core.somaxconn = 262144
net.ipv4.tcp_max_orphans = 3276800
net.ipv4.tcp_max_syn_backlog = 262144
net.ipv4.tcp_timestamps = 0
net.ipv4.tcp_synack_retries = 1
net.ipv4.tcp_syn_retries = 1
net.ipv4.tcp_tw_recycle = 1
net.ipv4.tcp_tw_reuse = 1
net.ipv4.tcp_mem = 94500000 915000000 927000000
net.ipv4.tcp_fin_timeout = 1
net.ipv4.tcp_keepalive_time = 30
net.ipv4.ip_local_port_range = 1024    65530
net.ipv4.icmp_echo_ignore_all = 1

3)   兩臺服務(wù)器分別添加一塊設(shè)備，用于DRBD主設(shè)備存儲，我這里為/dev/sdb 30G硬盤；

執(zhí)行如下命令：

mkfs.ext3 /dev/sdb ;dd if=/dev/zero of=/dev/sdb bs=1M count=1;sync

三、DRBD安裝配置

yum -y install drbd83* kmod-drbd83 ; modprobe  drbd

安裝完成并加載drbd模塊后，vi修改/etc/drbd.conf配置文件，本文內(nèi)容如下：

global {
    usage-count yes;
}
common {
syncer { rate 100M; }
}
resource r0 {
 protocol C;
 startup {

 }
 disk {
 on-io-error detach;
 #size 1G;
 }
 net {
 }
 on node1 {
 device /dev/drbd0;
 disk /dev/sdb;
 address 192.168.149.128:7898;
 meta-disk internal;
 }
 on node2 {
 device /dev/drbd0;
 disk /dev/sdb;
 address 192.168.149.129:7898;
 meta-disk internal;
 }
}

配置修改完畢后執(zhí)行如下命令初始化：

drbdadm create-md  r0  ;/etc/init.d/drbd restart ;/etc/init.d/status

如下圖:

以上步驟，需要在兩臺服務(wù)器都執(zhí)行，兩臺都配置完畢后，在node2從上面執(zhí)行如下命令：/etc/init.d/drbd status 看到如下信息，表示目前兩臺都為從，我們需要設(shè)置node1為master，命令如下：

drbdadm -- --overwrite-data-of-peer primary all
mkfs.ext3 /dev/drbd0
mkdir  /app  ;mount /dev/drbd0  /app

自此，DRBD配置完畢，我們可以往/app目錄寫入任何東西，當(dāng)master出現(xiàn)宕機(jī)或者其他故障，手動切換到backup，數(shù)據(jù)沒有任何丟失，相當(dāng)于兩臺服務(wù)器做網(wǎng)絡(luò)RAID1。

四、Keepalived配置

wget http://www./software/keepalived-1.1.15.tar.gz; tar -xzvf keepalived-1.1.15.tar.gz ;cd keepalived-1.1.15 ; ./configure ; make ;make install
DIR=/usr/local/ ;cp $DIR/etc/rc.d/init.d/keepalived  /etc/rc.d/init.d/ ; cp $DIR/etc/sysconfig/keepalived /etc/sysconfig/ ;
mkdir -p /etc/keepalived ; cp $DIR/sbin/keepalived /usr/sbin/

兩臺服務(wù)器均安裝keepalived，并進(jìn)行配置，首先在node1（master）上配置，keepalived.conf內(nèi)容如下：

! Configuration File for keepalived
global_defs {
   router_id LVS_DEVEL
}
vrrp_script check_mysql {
        script "/data/sh/check_mysql.sh"
        interval 5
        }
vrrp_instance VI_1 {
    state MASTER
    interface eth0
    virtual_router_id 52
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        192.168.149.100
         }
        track_script {
        check_mysql
        }
}

然后創(chuàng)建check_mysql.sh檢測腳本，內(nèi)容如下：

#!/bin/sh
A=`ps -C mysqld --no-header |wc -l`
if
[ $A -eq 0 ];then
/bin/umount /app/
drbdadm secondary r0
killall keepalived
fi

添加node2（backup）上配置，keepalived.conf內(nèi)容如下：

! Configuration File for keepalived
global_defs {
   router_id LVS_DEVEL
}
vrrp_sync_group VI{
group {
      VI_1
}
notify_master /data/sh/master.sh
notify_backup /data/sh/backup.sh
}
vrrp_instance VI_1 {
    state BACKUP
    interface eth0
    virtual_router_id 52
    priority 90
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        192.168.149.100
         }
}

創(chuàng)建master.sh檢測腳本，內(nèi)容如下：

#!/bin/bash
drbdadm primary r0
/bin/mount /dev/drbd0 /app/
/etc/init.d/mysqld start

創(chuàng)建backup.sh檢測腳本，內(nèi)容如下：

#!/bin/bash
/etc/init.d/mysqld stop
/bin/umount /dev/drbd0
drbdadm secondary r0

發(fā)生腦裂恢復(fù)步驟如下：

Master執(zhí)行命令：
drbdadm  secondary r0
drbdadm  --  --discard-my-data  connect r0
Backup上執(zhí)行命令：
drbdadm  connect r0

文章僅供參考，本文參考，特別感謝分享奉獻(xiàn)的IT人。

http://oldboy.blog.51cto.com/2561410/1240412

http://docs./ebooks/MySQL/Heartbeat+MySQL+DRBD%E6%9E%84%E5%BB%BA%E9%AB%98%E5%8F%AF%E7%94%A8MySQL%E6%96%B9%E6%A1%88.pdf