iSCSI Example on RHEL 7.2

Servers:
- iSCSI Target: akoya.spurrier.net.au – 192.168.1.26
- iSCSI Initiator: nuc1.spurrier.net.au – 192.168.1.27

Install iSCSI Target and Configure the Firewall

On each server:

subscription-manager register
subscription-manager attach --pool=8a85f98153dab2f00153dea83bf25daf
subscription-manager repos --enable rhel-7-server-rpms
yum make clean
yum repolist
yum groupinstall base
yum update
systemctl reboot

yum install firewalld
systemctl start firewalld.service
systemctl status firewalld.service
systemctl enable firewalld.service
firewall-cmd --permanent --add-service iscsi-target
firewall-cmd --reload

iSCSI Target – akoya.spurrier.net.au – 192.168.1.26

Ultimately I plan to try Gluster on this node but for now I want to practice with iSCSI so I created the future Gluster Brick below but instead used if as the backend to an iSCSI target. Sorry for any confusion.

Clean up “sdb” to use for the iSCSI target’s storage backend. (It had a Fedora install on it.)

pvs
fdisk -l /dev/sda
fdisk -l /dev/sdb
vgs  
lvs  
mount
# unmount any file systems on the disk to be repurposed.
pvs  
vgscan
vgchange -an fedora
pvremove /dev/sdb2 --force --force
# delete all partitions of the sdb disk.
fdisk /dev/sdb
pvcreate /dev/sdb
pvs  
vgcreate akoya_gfs1 /dev/sdb
lvcreate -l 100%FREE -n brick1 akoya_gfs1

We have an unformatted block device at /dev/akoya_gfs1/brick1. Get the iSCSI Initiator Name for the Target’s ACL before you begin. (See the first step in the next server’s block.) Lets make an iSCSI Target:

ll /dev/akoya_gfs1/
firewall-cmd --permanent --add-service iscsi-target
firewall-cmd --reload
yum install targetcli
systemctl start target
systemctl enable target
targetcli
    cd backstores/block
    create name=brick1 dev=/dev/akoya_gfs1/brick1
    cd ../../iscsi
    delete iqn.2003-01.org.linux-iscsi.akoya.x8664:sn.5bdc844021fa
    create iqn.2016-06.net.spurrier.akoya:gfs1-brick1
    cd iqn.2016-06.net.spurrier.akoya:gfs1-brick1/tpg1/luns
    create /backstores/block/brick1
    cd ../acls
    create iqn.1994-05.com.redhat:ff8456a7e3e0
    exit

iSCSI Initiator – nuc1.spurrier.net.au – 192.168.1.27

Check the iSCSI Initiator Name for adding to the ACL on the iSCSI Target (see above, iqn.1994-05.com.redhat:ff8456a7e3e0).

cat /etc/iscsi/initiatorname.iscsi 
    InitiatorName=iqn.1994-05.com.redhat:ff8456a7e3e0

Connect to the iSCSI Target:

yum install iscsi-initiator-utils
iscsiadm -m discovery -t st -p akoya
    192.168.1.26:3260,1 iqn.2016-06.net.spurrier.akoya:gfs1-brick1

iscsiadm -m node -T iqn.2016-06.net.spurrier.akoya:gfs1-brick1 -l

Confirm the iSCSI disk is “sdb”, format and mount:

ll /dev/sd*
fdisk -l /dev/sdb
fdisk -l /dev/sda
mkfs.xfs -L akoya_gfs1 /dev/sdb
mount /dev/sdb /mnt

Test by coping the root file system (/) to the mounted iSCSI volume:

df -h
mkdir /mnt/backup-nuc1
rsync -avPx / /mnt/backup-nuc1/
sync

(I threw in the “sync” as the root file system was so small (3GB) the writes were cached in RAM (16GB) and I had not seen any meaningful traffic with iotop. Yes the transfer rate was at my full 1Gb Ethernet speed.)

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