iSCSI Configuration

What is iSCSI 

iSCSI ( Internet Small Computer System Interface ) is an Internet Protocol (IP)-based storage networking standard for linking data storage facilities.

By carrying SCSI commands over IP networks, iSCSI is used to facilitate data transfers over intranets and to manage storage over long distances. iSCSI can be used to transmit data over local area networks (LANs), wide area networks (WANs), or the Internet and can enable location-independent data storage and retrieval.

The protocol allows clients (called initiators) to send SCSI commands (CDBs) to SCSI storage devices (targets) on remote servers. It is a storage area network (SAN) protocol, allowing organizations to consolidate storage into data center storage arrays while providing hosts (such as database and web servers) with the illusion of locally attached disks.

Configure Targets

In Ubuntu 14.04, simple setup: set the target device as a image file, no authentication required, can be connected from IP.

[1]	Create a new image file for storage area.

# create an image file of size 20G  root@dlp:~# mkdir /storage dd if=/dev/zero of=/storage/lun1.img bs=1024k count=20000

[2]	Configure iSCSI Target

root@dlp:~# aptitude -y install iscsitarget iscsitarget-dkms root@dlp:~# vi /etc/default/iscsitarget # change ISCSITARGET_ENABLE=true root@dlp:~# vi /etc/iet/ietd.conf # add at the last line # naming rule : [ iqn.yaer-month.domain:any name ] Target iqn.2014-04.world.server:target0   # provided devicce as a iSCSI target     Lun 0 Path=/storage/lun1.img,Type=fileio   # Alias     Alias LUN1   # authentication info ( set anyone you like for "username", "password" )     incominguser username password root@dlp:~# /etc/init.d/iscsitarget restart  * Removing iSCSI enterprise target devices: [ OK ] * Starting iSCSI enterprise target service [ OK ] [ OK ] root@dlp:~# ietadm --op show --tid=1  # show status Wthreads=8 Type=0 QueuedCommands=32 NOPInterval=0 NOPTimeout=0

Configure Initiator

Simple Setup: No authentication, assume target IP is 192.168.11.4

[1]	Configure iSCSI Initiator

root@www:~# aptitude -y install open-iscsi root@www:~# vi /etc/iscsi/iscsid.conf # discover target root@www:~# iscsiadm -m discovery -t sendtargets -p 192.168.11.4 192.168.11.4:3260,1 iqn.2012-07.world.server:target0 # confirm status after discovery root@www:~# iscsiadm -m node -o show  # BEGIN RECORD 2.0-871 node.name = iqn.2012-07.world.server:target0 node.tpgt = 1 node.startup = manual iface.hwaddress = <empty> iface.ipaddress = <empty> iface.iscsi_ifacename = default iface.net_ifacename = <empty> iface.transport_name = tcp iface.initiatorname = <empty> ... # END RECORD # login to target root@www:~# iscsiadm -m node --login ... # confirm session root@www:~#  iscsiadm -m session -o show  tcp: [1] 192.168.11.4:3260,1 iqn.2012-07.world.server:target0 # confirm partitions root@www:~# cat /proc/partitions

Reference

http://www.server-world.info/en/note?os=Ubuntu_12.04&p=iscsi
http://www.howtoforge.com/using-iscsi-on-ubuntu-10.04-initiator-and-target
http://en.wikipedia.org/wiki/ISCSI