How to Configure Storage Server with iSCSI in Redhat and Centos 7

yum -y install iscsi-initiator-utils

systemctl  enable iscsid
systemctl start iscsid

[root@centos7b ~]# fdisk -l

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: 0x000bfc92
Device Boot Start End Blocks Id System
/dev/sda1 * 2048 2099199 1048576 83 Linux
/dev/sda2 2099200 41943039 19921920 8e Linux LVM
Disk /dev/mapper/centos-root: 18.2 GB, 18249416704 bytes, 35643392 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 /dev/mapper/centos-swap: 2147 MB, 2147483648 bytes, 4194304 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

[root@centos7b ~]# vi /etc/iscsi/initiatorname.iscsi
InitiatorName=iqn.2018-04.org.osradar.com.centos7.share

 Check  if the  Port is opened on Target Server

[root@centos7b ~]# telnet centos7a 3260
Trying 192.168.65.131...
Connected to centos7a.
Escape character is '^]'.

[root@centos7b ~]# iscsiadm --mode discoverydb --type sendtargets --portal centos7a --discover
192.168.65.131:3260,1 iqn.2016-02.osradar.com
[root@centos7b ~]#

Please  remember the iqn name

 We are logged in..  nice!

 

fdisk /dev/sdb and create primary partition  /dev/sdb1

[root@centos7b ~]# fdisk /dev/sdb
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.

Device does not contain a recognized partition table
Building a new DOS disklabel with disk identifier 0x087d615e.

Command (m for help): n
Partition type:
 p primary (0 primary, 0 extended, 4 free)
 e extended
Select (default p): p
Partition number (1-4, default 1): 
First sector (8192-8388607, default 8192): 
Using default value 8192
Last sector, +sectors or +size{K,M,G} (8192-8388607, default 8388607): 
Using default value 8388607
Partition 1 of type Linux and of size 4 GiB is set

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

Calling ioctl() to re-read partition table.
Syncing disks.
[root@centos7b ~]#

new device has  been created

Format the Disk and create ext4 disk

[root@centos7b ~]# mkfs.ext4 /dev/sdb1 
mke2fs 1.42.9 (28-Dec-2013)
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
Stride=0 blocks, Stripe width=1024 blocks
262144 inodes, 1047552 blocks
52377 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=1073741824
32 block groups
32768 blocks per group, 32768 fragments per group
8192 inodes per group
Superblock backups stored on blocks: 
 32768, 98304, 163840, 229376, 294912, 819200, 884736

Allocating group tables: done 
Writing inode tables: done 
Creating journal (16384 blocks): done
Writing superblocks and filesystem accounting information: done

[root@centos7b ~]#

Create directory /data  and mount  the disk to  this folder

[root@centos7b ~]# mkdir /data 
[root@centos7b ~]# mount /dev/sdb1 /data
[root@centos7b ~]# df -h 
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/centos-root 17G 5.5G 12G 33% /
devtmpfs 477M 0 477M 0% /dev
tmpfs 488M 0 488M 0% /dev/shm
tmpfs 488M 6.8M 481M 2% /run
tmpfs 488M 0 488M 0% /sys/fs/cgroup
/dev/sda1 1014M 153M 862M 16% /boot
192.168.65.131:/nfs 17G 5.9G 12G 35% /nfsshare
tmpfs 98M 0 98M 0% /run/user/0
/dev/sdb1 3.9G 16M 3.7G 1% /data
[root@centos7b ~]#

/dev/sdb1 /data ext4 _netdev,defaults 0 0

 Reboot your System and Check  if the disk is mounted  automatically.

Enjoy