5.1 使用iSCSI磁碟
5.1.1 分割槽格式化
[root@host2 ~]# parted /dev/sda
(parted) mklabel gpt
(parted) mkpart primary 1M 100%
(parted) print
.........
(parted) quit
資訊: You may need to update /etc/fstab.
[root@host2 ~]# lsblk | awk '/sda/{print}'
sda 8:0 0 818M 0 disk
└─sda1 8:1 0 817M 0 part
#把/dev/sda1格式化成ext4格式
[root@host2 ~]# mkfs.ext4 /dev/sda1
# 檢視檔案系統及UUID
[root@host2 ~]# blkid /dev/sda1
/dev/sda1: UUID="2966d997-8efc-4974-b297-ca0578e948a5" TYPE="ext4" PARTLABEL="primary" PARTUUID="cf5bc374-bb72-4b25-a7f9-0b793ac9e662"
5.1.2 建立資料庫並寫入資料。
[root@host2 ~]# yum -y install mariadb mariadb-server
5.1.3 掛載再起服務
[root@host2 ~]# mount /dev/sda1 /var/lib/mysql/
[root@host2 ~]# chown mysql.mysql /var/lib/mysql/
[root@host2 ~]# systemctl start mariadb
5.2 測試
5.2.1 建立資料庫，並寫入資料
[root@host2 ~]# mysql -u root
MariaDB [(none)]> CREATE DATABASE chengdu DEFAULT CHAR SET utf8;
Query OK, 1 row affected (0.00 sec)
MariaDB [(none)]> use chengdu
Database changed
MariaDB [chengdu]> CREATE TABLE user(name varchar(20));
Query OK, 0 rows affected (0.01 sec)
MariaDB [chengdu]> INSERT INTO user VALUES ("李洋");
Query OK, 1 row affected (0.00 sec)
MariaDB [chengdu]> select * from user;
+--------+
| name |
+--------+
| 李洋 |
+--------+
1 row in set (0.00 sec)：
5.2.2.停止mariadb服務，解除安裝sda1（模擬vh02宕機了）
一定要將共享儲存解除安裝，不能vh02和vh03同時掛載共享儲存。因ext4/xfs是單節點檔案系統，如果多個節點同時掛載，就會損壞檔案系統，使得資料丟失。
[root@host2~]# systemctl stop mariadb
[root@host32~]# umount /dev/sda1 /var/lib/mysql/
5.2.3 在host03上掛載共享儲存，安裝資料庫，讓它為客戶機提供服務。
[root@host3 ~]# yum -y install iscsi-initiator-utils
[root@host3 ~]# rpm -q iscsi-initiator-utils
服務端設定：
新增客戶端訪問授權：如客戶端iqn名字是： iqn.2021-07.com.qq.www.host3(需回到服務端進行設定)。
[root@host1 ~]# targetcli
/> iscsi/iqn.2021-07.com.qq.www:chengdu/tpg1/acls/ create iqn.2021-07.com.qq.www.host3
Created Node ACL for iqn.2021-07.com.qq.www.host3
Created mapped LUN 0.
/> ls iscsi/iqn.2021-07.com.qq.www:chengdu/tpg1/acls/
o- acls ................................................................................ [ACLs: 2]
o- iqn.2021-07.com.qq.www.host2 ............................................... [Mapped LUNs: 1]
| o- mapped_lun0 .................................................... [lun0 block/formysql (rw)]
o- iqn.2021-07.com.qq.www.host3 ............................................... [Mapped LUNs: 1]
o- mapped_lun0 .................................................... [lun0 block/formysql (rw)]
/> saveconfig
Last 10 configs saved in /etc/target/backup.
Configuration saved to /etc/target/saveconfig.json
/> exit
客戶端設定：
[root@host3 ~]# vim /etc/iscsi/initiatorname.iscsi
InitiatorName=iqn.2021-07.com.qq.www.host3
[root@host3 ~]# iscsiadm --mode discoverydb --type sendtargets --portal 192.168.4.11 --discover
192.168.4.11:3260,1 iqn.2021-07.com.qq.www:chengdu
[root@host3 ~]# systemctl start iscsi
[root@host3 ~]# yum install -y mariadb-server
[root@host3 ~]# mount /dev/sda1 /var/lib/mysql/
[root@host3 ~]# systemctl start mariadb
[root@host3 ~]# mysql
MariaDB [(none)]> show databases;
+---------------------+
| Database |
+---------------------+
| information_schema |
| chengdu |
| #mysql50#lost+found |
| mysql |
| performance_schema |
| test |
+---------------------+
6 rows in set (0.01 sec)
MariaDB [(none)]> use chengdu
MariaDB [chengdu]> show tables;
+-------------------+
| Tables_in_chengdu |
+-------------------+
| user |
+-------------------+
1 row in set (0.00 sec)
MariaDB [chengdu]> select * from user
-> ;
+--------+
| name |
+--------+
| 李洋 |
+--------+
由此可發現同步過來了。