iSCSI(Internet SCSI):支持從客戶端通過IP向遠程服務器上的SCSI存儲設備發送SCSI命令
SCSI 結構基於客戶/服務器模式，其通常應用環境是：設備互相靠近，並且這些設備由 SCSI 總線連接。iSCSI 的主要功能是在 TCP/IP 網絡上的主機系統（啓動器 initiator）和存儲設備（目標器 target）之間進行大量數據的封裝和可靠傳輸過程。此外，iSCSI 提供了在 IP 網絡封裝 SCSI 命令，且運行在 TCP 上。
限定名稱格式：iqn.yyyy-mm.{reverse domain}:label
一、服務器端配置如下：
1.安裝並啓動服務
[root@localhost Desktop]# yum install targetcli -y #安裝iSCSI目標軟件包 [root@localhost Desktop]# systemctl start target #啓動target服務 [root@localhost Desktop]# systemctl enable target #設置服務開機自啓動
2.進入iSCSI交互式配置模式
[root@localhost Desktop]# targetcli #輸入targetcli命令
targetcli shell version 2.1.fb34
Copyright 2011-2013 by Datera, Inc and others.
For help on commands, type 'help'.
/> ls
o- / ..................................................................... [...]
o- backstores .......................................................... [...]
| o- block .............................................. [Storage Objects: 0]
| o- fileio ............................................. [Storage Objects: 0]
| o- pscsi .............................................. [Storage Objects: 0]
| o- ramdisk ............................................ [Storage Objects: 0]
o- iscsi ........................................................ [Targets: 0]
o- loopback ..................................................... [Targets: 0]
/> /backstores/block create pt.example.disk1 /dev/sda4 #使用/dev/sda4創建ISCSI遠程存儲塊pt.example.disk1
Created block storage object pt.example.disk1 using /dev/sda4.
/> /iscsi create iqn.2016-03.pt.example1:storage #創建要分享的ISCSI文件名（格式必須是iqn.yyyy-mm.{reverse domain}:label）
Created target iqn.2016-03.pt.example1:storage.
Created TPG 1.
/> /iscsi/iqn.2016-03.pt.example1:storage/tpg1/acls create iqn.2016-03.pt.example2:desktop #指定訪問ISCSI設備塊的ACL權限（即允許initiator name爲iqn.2016-03.pt.example2:desktop的客戶端可以訪問）
Created Node ACL for iqn.2016-03.pt.example2:desktop
/> /iscsi/iqn.2016-03.pt.example1:storage/tpg1/luns create /backstores/block/pt.example.disk1 #將創建的ISCSI遠程存儲塊加入進來
Created LUN 0.
Created LUN 0->0 mapping in node ACL iqn.2016-03.pt.example2:desktop
/> /iscsi/iqn.2016-03.pt.example1:storage/tpg1/portals create 172.25.254.209 #打開訪問所使用的端口
Using default IP port 3260
Created network portal 172.25.254.209:3260.
/> ls #完成後如下所示
o- / ..................................................................... [...]
o- backstores .......................................................... [...]
| o- block .............................................. [Storage Objects: 1]
| | o- pt.example.disk1 ............ [/dev/sda4 (1.0GiB) write-thru activated]
| o- fileio ............................................. [Storage Objects: 0]
| o- pscsi .............................................. [Storage Objects: 0]
| o- ramdisk ............................................ [Storage Objects: 0]
o- iscsi ........................................................ [Targets: 1]
| o- iqn.2016-03.pt.example1:storage ............................... [TPGs: 1]
| o- tpg1 ........................................... [no-gen-acls, no-auth]
| o- acls ...................................................... [ACLs: 1]
| | o- iqn.2016-03.pt.example2:desktop .................. [Mapped LUNs: 1]
| | o- mapped_lun0 .................. [lun0 block/pt.example.disk1 (rw)]
| o- luns ...................................................... [LUNs: 1]
| | o- lun0 ......................... [block/pt.example.disk1 (/dev/sda4)]
| o- portals ................................................ [Portals: 1]
| o- 172.25.254.209:3260 .......................................... [OK]
o- loopback ..................................................... [Targets: 0]
/> exit
Global pref auto_save_on_exit=true
Last 10 configs saved in /etc/target/backup.
Configuration saved to /etc/target/saveconfig.json設置防火牆
[root@localhost Desktop]# firewall-cmd --permanent --add-port=3260/tcp #將要使用的端口加入到防火牆允許之中 success [root@localhost Desktop]# firewall-cmd --reload #重載防火牆的設置 success
二、客戶端配置如下：
[root@localhost Desktop]# yum install iscsi-initiator-utils -y #安裝iSCSI發起端軟件包 [root@localhost Desktop]# vim /etc/iscsi/initiatorname.iscsi #設置發起端的IQN InitiatorName=iqn.2016-03.pt.example2:desktop [root@localhost Desktop]# iscsiadm -m discovery -t st -p 172.25.254.209 #獲得可以訪問共享的塊 172.25.254.209:3260,1 iqn.2016-03.pt.example1:storage [root@localhost Desktop]# iscsiadm -m node -T iqn.2016-03.pt.example1:storage -p 172.25.254.209 -l #連接服務端的ISCSI目標塊到本機 Logging in to [iface: default, target: iqn.2016-03.pt.example1:storage, portal: 172.25.254.209,3260] (multiple) Login to [iface: default, target: iqn.2016-03.pt.example1:storage, portal: 172.25.254.209,3260] successful. [root@localhost Desktop]# fdisk -l #查看磁盤，多了/dev/sdb Disk /dev/sda: 21.5 GB, 21474836480 bytes, 41943040 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk label type: dos Disk identifier: 0x000c235a Device Boot Start End Blocks Id System /dev/sda1 * 2048 411647 204800 83 Linux /dev/sda2 411648 4605951 2097152 82 Linux swap / Solaris /dev/sda3 4605952 35796991 15595520 83 Linux Disk /dev/sdb: 1073 MB, 1073741824 bytes, 2097152 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 4194304 bytes Disk label type: dos Disk identifier: 0x00000000 Device Boot Start End Blocks Id System
然後就可以正常使用所得到的ISCSI資源，正常格式化，並掛載。
########中斷使用ISCSI目標#########
先將掛載進行卸載，確保沒有使用目標所提供的任何設備
[root@localhost Desktop]# iscsiadm -m node -T iqn.2016-03.pt.example1:storage -p 172.25.254.209 -u #退出ISCSI目標，以暫時斷開連接 [root@localhost Desktop]# iscsiadm -m node -T iqn.2016-03.pt.example1:storage -p 172.25.254.209 -o -delete #刪除本地連接ISCSI目標的本地記錄，以永久斷開連接