centos7配置iscsi

什么是ISCSI

iscsi--internet small computer system interface互联小型计算机系统接口，将数据包封装在TCP/IP协议中传输，使用普通网线和网络设备即可实现，相对于FC-SAN存储来说更廉价。

ISCSI系统结构

iscsi一般分为服务器端和客户端，服务器端负责管理本地磁盘或磁盘陈列，客户端则是用来发现并连接服务器端获得访问iscsi共享盘。

centos7中服务端和客户端所需要的安装包

centos7	软件包
服务端	targetcli, targetd,scsi-target-utils
客户端	iscsi-initiator-utils

实验环境

角色	主机名	IP
服务端	master	192.168.138.200
客户端	slave	192.168.138.201

服务器端配置

• 准备一块磁盘并分好区，先不用格式化
• 运行targetcli命令，给要要共享的磁盘定义名字

# targetcli
targetcli shell version 2.1.fb46
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]
/> cd /backstores/block
/backstores/block> create slave /dev/sdb
Created block storage object slave using /dev/sdb.

• 创建iqn
  
  命名在同一子网内确保是唯一的，命名格式为：iqn.yyyy-mm.<主机名反写>:自定义名称

/backstores/block> cd /iscsi
/iscsi> create iqn.2018-02.com.frank.master:slave
Created target iqn.2018-02.com.frank.master:slave.
Created TPG 1.
Default portal not created, TPGs within a target cannot share ip:port.

• 创建acl允许ISCSI客户机连接

/iscsi> cd iqn.2018-02.com.frank.master:slave/tpg1/acls
/iscsi/iqn.20...ave/tpg1/acls> create iqn.2018-02.com.frank.master:slave
Created Node ACL for iqn.2018-02.com.frank.master:slave
/iscsi/iqn.20...ave/tpg1/acls> ls
o- acls .................................................... [ACLs: 1]
  o- iqn.2018-02.com.frank.master:slave ............. [Mapped LUNs: 0]

• 创建lun（target块设备的逻辑单元） 把块设备和iqn绑定

/iscsi> cd iqn.2018-02.com.frank.master:slave/tpg1/luns
/iscsi/iqn.20...ave/tpg1/luns> create /backstores/block/slave
Created LUN 0.
Created LUN 0->0 mapping in node ACL iqn.2018-02.com.frank.master:slave
/iscsi/iqn.20...ave/tpg1/luns> ls
o- luns .................................................... [LUNs: 1]
  o- lun0 ................ [block/slave (/dev/sdb) (default_tg_pt_gp)]

• 设置监听地址和端口

/iscsi/iqn.20.../tpg1/portals> create 192.168.138.200 ip_port=3260
Using default IP port 3260
Created network portal 192.168.138.200:3260.

这里要注意的是，使用ls查看一下是不是已经有0.0.0.0 3260这个条目，如果有删除掉再创建，不然会报错，还有一点的是如果 tgtd服务正在开启的情况下也无法创建，必须先停掉tgtd这个服务。

• 设置登录验证

/iscsi/iqn.20....master:slave> set auth userid=test
Parameter userid is now 'test'.
/iscsi/iqn.20....master:slave> set auth password=test
Parameter password is now 'test'.

到这里服务器的配置就算完成了，最后看一下配置完成的状态

/> ls
o- / ........................................................................... [...]
  o- backstores ................................................................ [...]
  | o- block .................................................... [Storage Objects: 1]
  | | o- slave ............................. [/dev/sdb (20.0GiB) write-thru activated]
  | |   o- alua ..................................................... [ALUA Groups: 1]
  | |     o- default_tg_pt_gp ......................... [ALUA state: Active/optimized]
  | o- fileio ................................................... [Storage Objects: 0]
  | o- pscsi .................................................... [Storage Objects: 0]
  | o- ramdisk .................................................. [Storage Objects: 0]
  o- iscsi .............................................................. [Targets: 1]
  | o- iqn.2018-02.com.frank.master:slave .................................. [TPGs: 1]
  |   o- tpg1 ................................................. [no-gen-acls, no-auth]
  |     o- acls ............................................................ [ACLs: 1]
  |     | o- iqn.2018-02.com.frank.master:slave ..................... [Mapped LUNs: 1]
  |     |   o- mapped_lun0 ................................... [lun0 block/slave (rw)]
  |     o- luns ............................................................ [LUNs: 1]
  |     | o- lun0 ........................ [block/slave (/dev/sdb) (default_tg_pt_gp)]
  |     o- portals ...................................................... [Portals: 1]
  |       o- 192.168.138.200:3260 ............................................... [OK]
  o- loopback ........................................................... [Targets: 0]
/>

• 启动服务端

# systemctl start tgtd.service

客户端配置

• 发现设备

# iscsiadm -m discovery -t sendtargets -p 192.168.138.200
iscsiadm: This command will remove the record [iface: default,
target: iqn.2018-04.com.frank.www:iscsi1, portal: 192.168.138.200,3260],
 but a session is using it. Logout session then rerun command to remove record.
192.168.138.200:3260,1 iqn.2018-02.com.frank.master:slave

• 连接设备

# iscsiadm -m node -T iqn.2018-02.com.frank.master:slave -p 192.168.138.200 --login
Logging in to [iface: default, target: iqn.2018-02.com.frank.master:slave,
  portal: 192.168.138.200,3260] (multiple)
Login to [iface: default, target: iqn.2018-02.com.frank.master:slave,
portal: 192.168.138.200,3260] successful.

• 查看设备

fdsik -l

WARNING: fdisk GPT support is currently new, and therefore in an experimental phase. Use at your own discretion.

Disk /dev/sdc: 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 / 4194304 bytes
Disk label type: gpt
#         Start          End    Size  Type            Name

# fdisk /dev/sdc

Command (m for help): n
Partition number (1-128, default 1):
First sector (34-41943006, default 8192):
Last sector, +sectors or +size{K,M,G,T,P} (8192-41943006, default 41943006): +10G
Created partition 1

Command (m for help): n
Partition number (2-128, default 2):
First sector (34-41943006, default 20979712):
Last sector, +sectors or +size{K,M,G,T,P} (20979712-41943006, default 41943006):
Created partition 2

Command (m for help): w
The partition table has been altered!

Calling ioctl() to re-read partition table.
Syncing disks.
[root@slave ~]# fdisk /dev/sdc
WARNING: fdisk GPT support is currently new, and therefore in an
experimental phase. Use at your own discretion.
Welcome to fdisk (util-linux 2.23.2).

Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.

Command (m for help): p

Disk /dev/sdc: 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 / 4194304 bytes
Disk label type: gpt

#         Start          End    Size  Type            Name
 1         8192     20979711     10G  Linux filesyste
 2     20979712     41943006     10G  Linux filesyste 

• 格式化分区并挂载

# mkfs.xfs /dev/sdc1
meta-data=/dev/sdc1              isize=512    agcount=4, agsize=610351 blks
         =                       sectsz=512   attr=2, projid32bit=1
         =                       crc=1        finobt=0, sparse=0
data     =                       bsize=4096   blocks=2441402, imaxpct=25
         =                       sunit=0      swidth=0 blks
naming   =version 2              bsize=4096   ascii-ci=0 ftype=1
log      =internal log           bsize=4096   blocks=2560, version=2
         =                       sectsz=512   sunit=0 blks, lazy-count=1
realtime =none                   extsz=4096   blocks=0, rtextents=0
[root@slave ~]# mkfs.xfs /dev/sdc2
meta-data=/dev/sdc2              isize=512    agcount=4, agsize=610291 blks
         =                       sectsz=512   attr=2, projid32bit=1
         =                       crc=1        finobt=0, sparse=0
data     =                       bsize=4096   blocks=2441162, imaxpct=25
         =                       sunit=0      swidth=0 blks
naming   =version 2              bsize=4096   ascii-ci=0 ftype=1
log      =internal log           bsize=4096   blocks=2560, version=2
         =                       sectsz=512   sunit=0 blks, lazy-count=1
realtime =none                   extsz=4096   blocks=0, rtextents=0
# mount /dev/sdc1 /iscsi/
# df -Th
Filesystem          Type      Size  Used Avail Use% Mounted on
/dev/mapper/cl-root xfs        37G   11G   27G  28% /
devtmpfs            devtmpfs  712M     0  712M   0% /dev
tmpfs               tmpfs     723M   12K  723M   1% /dev/shm
tmpfs               tmpfs     723M   72M  651M  10% /run
tmpfs               tmpfs     723M     0  723M   0% /sys/fs/cgroup
/dev/sda1           xfs      1014M  184M  831M  19% /boot
tmpfs               tmpfs     145M     0  145M   0% /run/user/0
/dev/sdc1           xfs       9.4G   33M  9.3G   1% /iscsi