In my lab setup, I have a host named server1.example.com, with an IP address of 192.168.1.112, which runs RHEL 6. This will be my iSCSI Target. A second host, named client1.example.com (192.168.1.11), which is also running RHEL 6, will be the iSCSI initator.
Solution:
Open-iSCSI project software feature are high-performance, transport independent, multi-platform implementation of RFC3720 iSCSI
Step to configure the iSCSI Target:
Creating the iSCSI Target
install scsi-target-utils
[root@server1 ~]# yum install scsi-target -y
Start the tgtd service
[root@server1 ~]# service tgtd start
Make the service persistent after reboots
[root@server1 ~]# chkconfig tgtd on
Note: The tgtd service hosts SCSI targets and uses the iSCSI protocol to enable communications between targets and initiators.
1. Create an LVM volume
[root@server1 ~]# fdisk -l
Disk /dev/sda: 8589 MB, 8589934592 bytes
255 heads, 63 sectors/track, 1044 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Device Boot Start End Blocks Id System
/dev/sda1 * 1 6 48163+ 83 Linux
/dev/sda2 7 853 6803527+ 83 Linux
/dev/sda3 854 903 401625 83 Linux
/dev/sda4 904 1044 1132582+ 5 Extended
/dev/sda5 904 977 594373+ 83 Linux
Create a raw partition
[root@server1 ~]# fdisk /dev/sda
The number of cylinders for this disk is set to 1044.
There is nothing wrong with that, but this is larger than 1024,
and could in certain setups cause problems with:
1) software that runs at boot time (e.g., old versions of LILO)
2) booting and partitioning software from other OSs
(e.g., DOS FDISK, OS/2 FDISK)
Command (m for help): n
First cylinder (978-1044, default 978):
Using default value 978
Last cylinder or +size or +sizeM or +sizeK (978-1044, default 1044): +200M
Command (m for help): t
Partition number (1-6): 6
Hex code (type L to list codes): 8e
Changed system type of partition 6 to 8e (Linux LVM)
Command (m for help): p
Disk /dev/sda: 8589 MB, 8589934592 bytes
255 heads, 63 sectors/track, 1044 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Device Boot Start End Blocks Id System
/dev/sda1 * 1 6 48163+ 83 Linux
/dev/sda2 7 853 6803527+ 83 Linux
/dev/sda3 854 903 401625 83 Linux
/dev/sda4 904 1044 1132582+ 5 Extended
/dev/sda5 904 977 594373+ 83 Linux
/dev/sda6 978 1002 200781 8e Linux LVM
Command (m for help): w
The partition table has been altered!
Calling ioctl() to re-read partition table.
WARNING: Re-reading the partition table failed with error 16: Device or resource busy.
The kernel still uses the old table.
The new table will be used at the next reboot.
Syncing disks.
[root@server1 ~]# partx -a /dev/sda
Create physical volume
[root@server1 ~]# pvcreate /dev/sda6
Physical volume "/dev/sda6" successfully created
Create volume group
[root@server1 ~]# vgcreate vol01 /dev/sda6
Volume group "vol01" successfully created
Create logical volume
[root@server1 ~]# lvcreate -L 150M -n log01 vol01
Rounding up size to full physical extent 152.00 MB
Logical volume "log01" created
2. Create file-based images
Create a new directory to store the image file
[root@server1 ~]# mkdir -p /var/lib/tgtd/virtualization
Create an image named virtimage2.img with a size of 100M.
[root@server1 ~]# dd if=/dev/zero of=/var/lib/tgtd/virtualization/virtimage2.img bs=1M seek=100 count=0
Configure the correct SELinux context for the new image and directory.
[root@server1 ~]# restorecon -R /var/lib/tgtd
Check the SELinux context for the new image and directory.
[root@server1 ~]# ls -ldZ /var/lib/tgtd/
drwxr-xr-x root root root:object_r:var_lib_t:s0 /var/lib/tgtd/
Note: Targets can be created by adding an XML entry to the /etc/tgt/targets.conf file. The target attribute requires an iSCSI Qualified Name (IQN), in the format:
iqn.yyyy-mm.reversed.domain.name:OptionalIdentifierText
where:
yyyy-mm represents the 4-digit year and 2-digit month the device was started (for example: 2011-08);
reversed.domain.name is the hosts domain name in reverse. For example, server1.example.com, in an IQN, becomes com.example.server1; and
OptionalIdentifierText is any text string, without spaces, that helps the administrator identify which device is which.
Create the target
[root@server1 ~]# vim /etc/tgt/targets.conf
### At last add the following lines ###
<target iqn.2011-07.com.example.server1:trial>
backing-store /dev/vol01/log01 #LUN1
backing-store /var/lib/tgtd/virtualization/virtimage2.img #LUN2
write-cache off
</target>
Save and quite
:wq
Note: Ensure that the /etc/tgt/targets.conf file contains the default-driver iscsi line to set the driver type as iSCSI (the driver uses iSCSI by default, but make sure that line is not commented out).
[root@server1 ~]# grep default-driver /etc/tgt/targets.confdefault-driver iscsi
IPTables configuration:
[root@server1 ~]# iptables -I INPUT -m tcp -p tcp --dport 3260 -j ACCEPT
[root@server1 ~]# service iptables save
[root@server1 ~]# service iptables restart
verify the new iscsi target
[root@server1 ~]# tgt-admin --show
Target 1: iqn.2011-07.com.example.server1:trial
System information:
Driver: iscsi
State: ready
I_T nexus information:
LUN information:
LUN: 0
Type: controller
SCSI ID: IET 00010000
SCSI SN: beaf10
Size: 0 MB
Online: Yes
Removable media: No
Backing store type: null
Backing store path: None
Backing store flags:
LUN: 1
Type: disk
SCSI ID: IET 00010001
SCSI SN: beaf11
Size: 159 MB
Online: Yes
Removable media: No
Backing store type: rdwr
Backing store path: /dev/vol01/log01
Backing store flags:
LUN: 2
Type: disk
SCSI ID: IET 00010002
SCSI SN: beaf12
Size: 105 MB
Online: Yes
Removable media: No
Backing store type: rdwr
Backing store path: /var/lib/tgtd/virtualization/virtimage2.img
Backing store flags:
Account information:
ACL information:
ALL
Step to configure the ISCSI-initiator:
Install ISCSI-initiator
[root@server1 ~]# yum install iscsi-initiator -y
Start the iscsi service
# service iscsid start
Make the service persistent after reboots
[root@server1 ~]# chkconfig iscsid on
Now we can test whether the new iSCSI device is discoverable from client1.example.com:
[root@server1 ~]# iscsiadm -m discovery -t sendtargets -p server1.example.com
192.168.1.112:3260,1 iqn.2011-07.com.example.server1:trial
or
[root@server1 ~]# iscsiadm -m discovery -t sendtargets -p 192.168.1.112
192.168.1.112:3260,1 iqn.2011-07.com.example.server1:trial
Note: 192.168.1.112 is the ip address of your own iscsi target server
To view more information about your iSCSI Target
[root@server1 ~]# iscsiadm -m node -T iqn.2011-07.com.example.server1:trial -p 192.168.1.112
# BEGIN RECORD 2.0-872
node.name = iqn.2011-07.com.example.server1:trial
node.tpgt = 1
node.startup = automatic
iface.hwaddress = <empty>
iface.ipaddress = <empty>
iface.iscsi_ifacename = default
iface.net_ifacename = <empty>
iface.transport_name = tcp
iface.initiatorname = <empty>
node.discovery_address = 192.168.1.112
node.discovery_port = 3260
node.discovery_type = send_targets
node.session.initial_cmdsn = 0
node.session.initial_login_retry_max = 8
node.session.xmit_thread_priority = -20
node.session.cmds_max = 128
node.session.queue_depth = 32
node.session.auth.authmethod = None
node.session.auth.username = <empty>
node.session.auth.password = <empty>
node.session.auth.username_in = <empty>
node.session.auth.password_in = <empty>
node.session.timeo.replacement_timeout = 120
node.session.err_timeo.abort_timeout = 15
node.session.err_timeo.lu_reset_timeout = 30
node.session.err_timeo.tgt_reset_timeout = 30
node.session.err_timeo.host_reset_timeout = 60
node.session.iscsi.FastAbort = Yes
node.session.iscsi.InitialR2T = No
node.session.iscsi.ImmediateData = Yes
node.session.iscsi.FirstBurstLength = 262144
node.session.iscsi.MaxBurstLength = 16776192
node.session.iscsi.DefaultTime2Retain = 0
node.session.iscsi.DefaultTime2Wait = 2
node.session.iscsi.MaxConnections = 1
node.session.iscsi.MaxOutstandingR2T = 1
node.session.iscsi.ERL = 0
node.conn[0].address = 192.168.1.112
node.conn[0].port = 3260
node.conn[0].startup = manual
node.conn[0].tcp.window_size = 524288
node.conn[0].tcp.type_of_service = 0
node.conn[0].timeo.logout_timeout = 15
node.conn[0].timeo.login_timeout = 15
node.conn[0].timeo.auth_timeout = 45
node.conn[0].timeo.noop_out_interval = 5
node.conn[0].timeo.noop_out_timeout = 5
node.conn[0].iscsi.MaxXmitDataSegmentLength = 0
node.conn[0].iscsi.MaxRecvDataSegmentLength = 262144
node.conn[0].iscsi.HeaderDigest = None
node.conn[0].iscsi.IFMarker = No
node.conn[0].iscsi.OFMarker = No
# END RECORD
Log into the iSCSI target
[root@server1 ~]# iscsiadm -m node -T iqn.2011-07.com.example.server1:trial -p 192.168.1.112 -l
Logging in to [iface: default, target: iqn.2011-07.com.example.server1:trial, portal: 192.168.1.112,3260]
Login to [iface: default, target: iqn.2011-07.com.example.server1:trial, portal: 192.168.1.112,3260] successful.
Check the logs for disk partion name is available
[root@server1 ~]# tail -f /var/log/messages
Aug 17 02:03:46 server1 kernel: scsi2 : iSCSI Initiator over TCP/IP
Aug 17 02:03:46 server1 kernel: Vendor: IET Model: Controller Rev: 0001
Aug 17 02:03:46 server1 kernel: Type: RAID ANSI SCSI revision: 05
Aug 17 02:03:46 server1 kernel: scsi 2:0:0:0: Attached scsi generic sg1 type 12
Aug 17 02:03:46 server1 kernel: Vendor: IET Model: VIRTUAL-DISK Rev: 0001
Aug 17 02:03:46 server1 kernel: Type: Direct-Access ANSI SCSI revision: 05
Aug 17 02:03:46 server1 kernel: SCSI device sdb: 311296 512-byte hdwr sectors (159 MB)
Aug 17 02:03:46 server1 kernel: sdb: Write Protect is off
Aug 17 02:03:46 server1 kernel: SCSI device sdb: drive cache: write through
Aug 17 02:03:46 server1 kernel: SCSI device sdb: 311296 512-byte hdwr sectors (159 MB)
Aug 17 02:03:46 server1 kernel: sdb: Write Protect is off
Aug 17 02:03:46 server1 kernel: SCSI device sdb: drive cache: write through
Aug 17 02:03:46 server1 kernel: sdb: unknown partition table
Aug 17 02:03:46 server1 kernel: sd 2:0:0:1: Attached scsi disk sdb
Aug 17 02:03:46 server1 kernel: sd 2:0:0:1: Attached scsi generic sg2 type 0
Aug 17 02:03:46 server1 kernel: Vendor: IET Model: VIRTUAL-DISK Rev: 0001
Aug 17 02:03:46 server1 kernel: Type: Direct-Access ANSI SCSI revision: 05
Aug 17 02:03:46 server1 kernel: SCSI device sdc: 204800 512-byte hdwr sectors (105 MB)
Aug 17 02:03:46 server1 kernel: sdc: Write Protect is off
Aug 17 02:03:46 server1 kernel: SCSI device sdc: drive cache: write through
Aug 17 02:03:46 server1 kernel: SCSI device sdc: 204800 512-byte hdwr sectors (105 MB)
Aug 17 02:03:46 server1 kernel: sdc: Write Protect is off
Aug 17 02:03:46 server1 kernel: SCSI device sdc: drive cache: write through
Aug 17 02:03:46 server1 kernel: sdc: unknown partition table
Aug 17 02:03:46 server1 kernel: sd 2:0:0:2: Attached scsi disk sdc
Aug 17 02:03:46 server1 kernel: sd 2:0:0:2: Attached scsi generic sg3 type 0
Aug 17 02:03:46 server1 iscsid: Could not set session1 priority. READ/WRITE throughout and latency could be affected.
Aug 17 02:03:46 server1 iscsid: Connection1:0 to [target: iqn.2011-07.com.example.server1:trial, portal: 192.168.1.112,3260] through [iface: default] is operational now
Note: Now the target is enabled to be accessed upon reboots (persistent) and it's added to a node database in /var/lib/iscsi
Check the partition table
[root@server1 ~]# fdisk -l
Disk /dev/sda: 8589 MB, 8589934592 bytes
255 heads, 63 sectors/track, 1044 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Device Boot Start End Blocks Id System
/dev/sda1 * 1 6 48163+ 83 Linux
/dev/sda2 7 853 6803527+ 83 Linux
/dev/sda3 854 903 401625 83 Linux
/dev/sda4 904 1044 1132582+ 5 Extended
/dev/sda5 904 977 594373+ 83 Linux
/dev/sda6 978 1002 200781 8e Linux LVM
Disk /dev/sdb: 159 MB, 159383552 bytes
5 heads, 61 sectors/track, 1020 cylinders
Units = cylinders of 305 * 512 = 156160 bytes
Disk /dev/sdb doesn't contain a valid partition table
Disk /dev/sdc: 104 MB, 104857600 bytes
4 heads, 50 sectors/track, 1024 cylinders
Units = cylinders of 200 * 512 = 102400 bytes
Disk /dev/sdc doesn't contain a valid partition table
Create partition Disk
[root@server1 ~]# fdisk /dev/sdc
p -->Print partition
n -->Create new partition
p -->Primary partition
2 -->partition Number
Enter -->starting cylinder
+100M -->size of the partition
p -->Print partition
w -->Write and save the partition
Reboot or refresh the kernel partition table by using partx command
[root@server1 ~]# partx -a /dev/sdb
Format Disk
[root@server1 ~]# mkfs.ext3 /dev/sdb2
create directory /iscsidata
[root@server1 ~]#mkdir /iscsidata
mount disk(/dev/sdb) to mount point(/iscsidata)
[root@server1 ~]# mount /dev/sdb2 /iscsidata
check the the filesystem is mounted or not
[root@server1 ~]# df -h
Mount the partition at boot. create a enty in the /etv/fstab file
[root@server1 ~]# vim /etc/fstab
/dev/sdb2 /iscsidata ext3 _netdev 0 0
mount all the partition which is exists in the /etc/fstab
[root@server1 ~]# mount -a
check the the filesystem is mounted or not
[root@server1 ~]# mount | grep iscsi
check the disk
# df -h
2 comments:
nice one... good job.. but, i m getting: while mounting scsi disk on initiator:
# mke2fs -j /dev/sdc1
mke2fs 1.41.12 (17-May-2010)
/dev/sdc1 is apparently in use by the system; will not make a filesystem here!
Greate job
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