Configuring iSCSI in SLES

After SLES is installed, run the rpm -qa |grep iscsi command to check whether the iSCSI software is installed.

linux-epl0:~/SPES_FOR_LINUX-2012.08.16 # rpm -qa |grep iscsi  
yast2-iscsi-client-2.17.34-0.5.1  
open-iscsi-2.0.872-0.35.1  
yast2-iscsi-server-2.17.10-0.7.3

The output shows that the iSCSI software has been installed.

If the iSCSI software is not installed or the installed iSCSI software is of an early version, use the YaST tool to install or upgrade the software.

1. On the CLI, enter yast to start the YaST tool.

   linux-epl0:~/open-iscsi-2.0-870.2 # yast

   Figure 4-304 YaST CLI
   

   In the menu on the left, choose Software, as shown in Figure 4-304.

2. In the menu on the right, choose Software Management, as shown in Figure 4-305.
   Figure 4-305 Choosing Software Management
   
3. In Search, enter iscsi to query iSCSI software packages.
   Figure 4-306 Querying iSCSI software packages
   
4. In the output that is displayed, choose the iSCSI software package that you want to install.
   Figure 4-307 Choosing an iSCSI software installation package
   
5. In the output that is displayed, choose Action and press Enter. In the menu that is displayed, choose Install.
   Figure 4-308 Choosing Install
   
6. Choose Accept to start the software installation.
   Figure 4-309 Starting the software installation
   

7. After the installation is complete, choose Quit to exit YaST.

Figure 4-310 Exiting YaST

The supported IP protocols vary with the storage system version. Specify the IP protocol based on the actual storage system version and application scenario.

Observe the following rules when configuring IP addresses for the iSCSI ports of the storage system:

• The IP address of the iSCSI host port cannot reside on the same network segment as the IP address of the management network port.
• The IP address of the iSCSI host port cannot reside on the same network segment as the IP address of the heartbeat network port.
• The IP addresses of the iSCSI host ports of the same controller must reside on different network segments. In some storage systems of the latest versions, IP addresses of iSCSI host ports on the same controller can reside on the same network segment. However, this configuration is not recommended.

Read-only users cannot modify the IP addresses of iSCSI host ports.

Modifying an IP address will interrupt services running on the host port.

This section describes how to use the YaST tool to configure the IP address. Perform the following steps:

1. Go to the YaST tool management CLI and choose Network Devices.
   Figure 4-311 Choosing Network Devices
   
2. Choose Network Settings to configure the network.
   Figure 4-312 Choosing Network Settings
   
3. Choose a network adapter to be configured.
   Figure 4-313 Choosing a network adapter
   
4. Press Tab to choose Edit.
   Figure 4-314 Configuring the IP address and subnet mask
   
5. Enter the IP address and subnet mask.
   Figure 4-315 Entering the IP address and subnet mask
   

   Click Next.

6. After configuring the network, choose OK on the Network Settings screen to activate the configuration.
   Figure 4-316 Activating the configuration
   
7. After IP addresses are configured for the host and the storage system, run the ping command to check the link connectivity. If the link connectivity is poor, check the physical links and IP address configurations.

   [root@root ~]# ping 100.100.100.2  
   PING 100.100.100.2 (100.100.100.2) 56(84) bytes of data.  
   64 bytes from 100.100.100.2: icmp_seq=1 ttl=64 time=0.607 ms  
   64 bytes from 100.100.100.2: icmp_seq=2 ttl=64 time=0.181 ms  
   64 bytes from 100.100.100.2: icmp_seq=3 ttl=64 time=0.159 ms  
   ^C  
   --- 100.100.100.2 ping statistics ---  
   3 packets transmitted, 3 received, 0% packet loss, time 2399ms  
   rtt min/avg/max/mdev = 0.159/0.315/0.607/0.207 ms

Run the iscsiadm command to configure the host initiator.

1. Start the iSCSI service.

   linux-epl0:~ # /etc/init.d/open-iscsi start  
   Loading iscsi modules: done  
   Starting iSCSI initiator service: done  
   Setting up iSCSI targets: unused

2. View the host initiator information.

   [root@root ~]#cat /etc/iscsi/initiatorname.iscsi  
   InitiatorName=iqn.2012-10.com.example:d0104b56adc6

   The output shows that the name of the host initiator is iqn.2012-10.com.example:d0104b56adc6.

   Rules for setting an iSCSI initiator name:

   Format: iqn.domaindate.reverse.domain.name:optional name

   An iSCSI initiator name contains only:

   • Special characters: hyphens (-), periods (.), and semicolons (:)
   • Lower-case letters (a to z)
   • Digits (0 to 9)

   An iSCSI initiator name can contain a maximum of 223 characters.

   In some OSs, the host initiator name is left blank. You need to configure this parameter by modifying a configuration file or using the YaST tool.

3. Query the target.

   For example, if the service IP address of the storage port is 100.100.100.2, run the following command on the host to query the target:

   linux-epl0:~ # iscsiadm -m discovery -t st -p 100.100.100.2  
   100.100.100.2:3260,260 iqn.2006-08.com.huawei:oceanstor:21000022a10b7bb2::20103:100.100.100.2

4. Log in to the target.

   linux-epl0:~ # iscsiadm -m node -p 100.100.100.2 -l  
   Logging in to [iface: default, target: iqn.2006-08.com.huawei:oceanstor:21000022a10b7bb2::20103:100.100.100.2, portal: 100.100.100.2,3260] (multiple)  
   Login to [iface: default, target: iqn.2006-08.com.huawei:oceanstor:21000022a10b7bb2::20103:100.100.100.2, portal: 100.100.100.2,3260] successful.

5. Configure the open-iscsi service to run upon system startup

   linux-epl0:~ # chkconfig open-iscsi on

6. If CHAP authentication is not required between the storage system and the host, the host initiator configuration is completed. If CHAP authentication is required, run the iscsiadm command.

   linux-epl0:~ #iscsiadm -m node -o update -p 100.100.100.2 -n node.session.auth.authmethod -v CHAP  
   linux-epl0:~ # iscsiadm -m node -o update -p 100.100.100.2 -n node.session.auth.username -v root  
   linux-epl0:~ # iscsiadm -m node -o update -p 100.100.100.2 -n node.session.auth.password -v huawei123456  
   linux-epl0:~ # /etc/init.d/open-iscsi restart 
   Stopping iSCSI daemon:  
   iscsid dead but pid file exists [ OK ]  
   Turning off network shutdown. Starting iSCSI daemon: [ OK ]  
   [ OK ]  
   Setting up iSCSI targets: Logging in to [iface: default, target: iqn.2006-08.com.huawei:oceanstor:21000022a10b7bb2::100.100.100.2-20100, portal: 100.100.100.2,3260]  
   Login to [iface: default, target: iqn.2006-08.com.huawei:oceanstor:21000022a10b7bb2::100.100.100.2-20100, portal: 100.100.100.2,3260]: successful  
   [ OK ]

   The user name and password in the commands must be the same as the initiator name and password configured on the storage system; otherwise, the connection cannot be established.

   The command syntax is as follows:

   iscsiadm -m node -o update -p targetip -n node.session.auth.authmethod -v CHAP

   iscsiadm -m node -o update -p targetip -n node.session.auth.username -v username

   iscsiadm -m node -o update -p targetip -n node.session.auth.password -v password

   This command is also applicable to adding CHAP authentication to multiple targets.

   You are advised to run the iscsiadm command to modify related parameters. Do not modify the parameters using the configuration file.

The initiator configured on the host is identified by the ISM. You need to manually add the identified initiator to the host.

• OceanStor T V1 series storage

  To configure the OceanStor T V1 series storage, perform the following steps:

  1. In the ISM navigation tree, choose SAN Services > Mappings > Initiators. In the function pane, select the initiator that you want to add to the host and click Add to Host.
     Figure 4-317 Selecting an initiator
     
  2. Select the host to which the initiator is added.
     Figure 4-318 Adding an initiator to the host
     
  3. If CHAP authentication is not required between the storage system and the host, the host initiator configuration is completed. If CHAP authentication is required, proceed with the following steps to configure CHAP authentication on the storage system.

     The following steps describe how to configure CHAP authentication on the storage system.

  4. In the ISM navigation tree, choose SAN Services > Mappings > Initiators. In the function pane, select the initiator whose CHAP authentication you want to configure and choose CHAP > CHAP Configuration in the navigation bar.
     Figure 4-319 Initiator CHAP configuration
     
  5. In the CHAP Configuration dialog box that is displayed, click Create in the lower right corner.
     Figure 4-320 CHAP Configuration dialog box
     

     In the Create CHAP dialog box that is displayed, enter the CHAP user name and password.

     Figure 4-321 Create CHAP dialog box
     

     The CHAP user name contains 4 to 25 characters and the password contains 12 to 16 characters. The limitations on the CHAP user name and password vary with the storage system. For details, see the help documentation of the storage system.

     Assign the CHAP user name and password to the initiator.

     Figure 4-322 Assigning the CHAP account to the initiator
     
  6. Enable the CHAP account that is assigned to the host.

     In the ISM navigation tree, choose SAN Services > Mappings > Initiators. In the function pane, select the initiator whose CHAP account is to be enabled and choose CHAP > Status Settings in the navigation bar.

Figure 4-323 Setting the CHAP status

In the Status Settings dialog box that is displayed, choose Enabled from the CHAP Status drop-down list.

Figure 4-324 Enabling CHAP

Figure 4-325 shows the initiator status in the ISM.

Figure 4-325 Initiator status after CHAP is enabled

Run the rescan-scsi-bus.sh script on a SLES host to scan for LUNs.

If rescan-scsi-bus.sh is not found, run the rpm -qa | grep sg3 command to check whether sg3_utils-libs-xx-xx and sg3_utils-xx-xx are installed. If they are not installed, install them.

Perform the following steps to scan for LUNs:

1. Add LUNs to the host on the storage system and then run the following command on the host to scan for the LUNs:

   [root@root ~]# rescan-scsi-bus.sh  
   Host adapter 0 (megaraid_sas) found.  
   Host adapter 1 (ata_piix) found.  
   Host adapter 10 (iscsi_tcp) found.  
   Host adapter 2 (ata_piix) found.  
   Host adapter 3 (bnx2i) found.  
   Host adapter 4 (bnx2i) found.  
   Host adapter 5 (bnx2i) found.  
   Host adapter 6 (bnx2i) found.  
   Scanning SCSI subsystem for new devices  
   Scanning host 0 for SCSI target IDs 0 1 2 3 4 5 6 7, all LUNs  
   Scanning for device 0 2 0 0 ...  
   OLD: Host: scsi0 Channel: 02 Id: 00 Lun: 00  
   Vendor: DELL Model: PERC H700 Rev: 2.10  
   Type: Direct-Access ANSI SCSI revision: 05  
   Scanning host 1 channels 0 2 for SCSI target IDs 0 1 2 3 4 5 6 7, all LUNs  
   Scanning for device 1 0 0 0 ...  
   OLD: Host: scsi1 Channel: 00 Id: 00 Lun: 00  
   Vendor: TSSTcorp Model: DVD-ROM SN-108BB Rev: D150  
   Type: CD-ROM ANSI SCSI revision: 05  
   Scanning host 2 channels 0 2 for SCSI target IDs 0 1 2 3 4 5 6 7, all LUNs  
   Scanning host 3 for all SCSI target IDs, all LUNs  
   Scanning host 4 for all SCSI target IDs, all LUNs  
   Scanning host 5 for all SCSI target IDs, all LUNs  
   Scanning host 6 for all SCSI target IDs, all LUNs  
   Scanning host 10 for all SCSI target IDs, all LUNs  
   Scanning for device 10 0 0 0 ...  
   OLD: Host: scsi10 Channel: 00 Id: 00 Lun: 00  
   Vendor: HUAWEI Model: S2600T Rev: 2105  
   Type: Direct-Access ANSI SCSI revision: 04  
   0 new device(s) found.  
   0 device(s) removed.

2. Query LUN information on the host.

   linux-epl0:~ # fdisk -l  
   Disk /dev/sda: 598.8 GB, 598879502336 bytes  
   255 heads, 63 sectors/track, 72809 cylinders  
   Units = cylinders of 16065 * 512 = 8225280 bytes  
   Device Boot Start End Blocks Id System  
   /dev/sda1 * 1 13 104391 83 Linux  
   /dev/sda2 14 72809 584733870 8e Linux LVM  
   Disk /dev/sdb: 104 MB, 104857600 bytes  
   4 heads, 50 sectors/track, 1024 cylinders  
   Units = cylinders of 200 * 512 = 102400 bytes

3. If the newly added LUNs cannot be identified on the host, perform as follows:

• Restart the open-iscsi service: Run the /etc/init.d/open-iscsi restart command to restart the service.
• Re-log in to the iSCSI initiator: Run the iscsiadm -m node -u and iscsiadm -m node -l commands to log out of and log in to the iSCSI initiator.