Migrating a NetWare iSCSI Target to a Linux iSCSI Target on SLES 10


This AppNote describes how to migrate from a NetWare iSCSI target to a Linux iSCSI target on SLES 10. The basic idea is to use a SLES 10 server as the iSCSI target server. After configuring the Linux server as the iSCSI target, any Linux initiator can contact the target server in the network. This is a pure Linux iSCSI based setup with the initiator as well as the target as Linux servers.

Customers who have a NetWare server as the iSCSI target server and OES Linux servers as the cluster nodes can use the following steps to add a Linux SLES 10 server in their existing setup as the new target server and configure the existing Linux initiators for the new target.

Note: It is assumed that a setup for two (minimum) node Linux clusters (OES SP2) is up and working with a NetWare server as the iSCSI target server. The following method gives you the steps to add your new Linux iSCSI target server in an existing setup and how to configure that server as the target server with the existing Linux nodes reconfigured for the new target server.

This is a manual migration of the iSCSI target for NetWare to Linux. This AppNote does not give any steps to migrate a full NetWare server to Linux server.

Table of Contents

  1. Introduction
  2. Minimum system requirements
  3. Linux SLES 10 target Installation
  4. iSCSI target configuration on SLES 10
  5. Starting iSCSI target Manually
  6. iSCSI initiator configuration on the existing Linux nodes
  7. Filesystem creation on the cluster node
  8. Data restore on iscsi partition and new cluster resource creation
  9. Conclusion
  10. Related links

1. Introduction:

iSCSI – The iSCSI protocol combines the use of block-level data movement with TCP/IP networks. By allowing SCSI commands to travel through IP networks, high-speed IP networking technology can carry data from storage units to servers anywhere throughout a corporate network Also referred to as IP storage.

Now iSCSI target is available on the SLES 10 server. The information given below is to configure iSCSI target on the SLES 10 server and reconfigure iSCSI initiator for the new target.
The basic idea here is to use Linux server as the iSCSI target server instead of NetWare server. Since this is a migration scenario we should make sure that existing data residing on the iSCSI NetWare target should be backed up.

2. Minimum system requirements:

  • One server class machine
  • Software requirements: SLES 10 Server build

3. Linux Installation:

Install SLES 10 server on the new hardware and select following packages

  • iscsitarget
  • yast2-iscsi client
  • yast2-iscsi server

These packages are required to configure iSCSI target on SLES 10.

4. iSCSI target configuration on SLES 10 server:

Before configuring iSCSI target create a block device on the SLES 10 server. Goto partition and create a Linux partition like /dev/hdax (or /dev/sdax) on the server and do no format that partition.

Yast2 -> System -> partitioner and create partition as shown below. This is your /dev/hda3 as shown below.

Do not format this partition.

Configure iSCSI target using the following steps:

Step 1: Goto Yast2 -> Network services -> iscsitarget

You can open the configuration of iSCSI target from the terminal.

Type: yast2 iscsi-server

Step 2: Select service and check radio button “when booting” in the service start.

Step 3: Goto targets: If there is already a target present, delete the target and add new one.

Click on Add – this will display following screen.

Select Path and add the path of the partition you have created above ( /dev/hda3)

Step 4: Click on finish to end the configuration. This will start the target automatically.

5. Starting iSCSI target manually:

  • To start iSCSI target give the following command in the Linux terminal:

    /etc/init.d/iscsitarget start

    This will start the iSCSI target on the SLES 10 server
    You can use rciscsitarget restart in the terminal.

  • To view the active targets on the Linux machine, type in the terminal:

    cat /proc/net/iet/volumes

    This will display the targets that exists on the server as shown below.

  • To display the initiator connected to the iSCSI target type:

    cat /proc/net/iet/session

6. ISCSI initiators configuration on the existing Linux nodes.

Before configuring Linux initiator make sure that backup of the existing data on the shared resource is taken. Once this is done follow the steps given below.

Step 1: Stop iscsi on every node. In the terminal type:

/etc/init.d/iscsi stop

Step 2: Open the iscsi.conf file on every node of the cluster and add the discovery address, LUN and target name in this file. Comment the previous Discovery address and Target Name in this file and add this line:

vi /etc/iscsi.conf

Add the following lines at the end of the file:

DiscoveryAddress=<IP address of SLES 10 target server>
TargetName=<iscsi target name>

Note: To get the iscsi target name, do ssh to the target server from the local Linux server and type:

cat /proc/net/iet/volumes

This will display the target name. Copy and paste the target name in the iscsi.conf file.

Step 3: Open the initiatorname file and remove the field after the colon and add the target server system name.

Step 4: Start the iSCSI initiators on the Linux nodes.

/etc/init.d/iscsi start

A pop up will show the iSCSI partition.

Repeat steps 2, 3 and 4 on every node of the clusters.

7. File system creation on the cluster nodes

Go to the cluster nodes and Goto yast2->partitioner and select the iscsi partition and create a Linux reiserfs partition and give mount point.

A NSS or VFS file system can be created by selecting the iSCSI partition.

8. Data restore on the iSCSI partition and cluster resource creation.

Create the file system on any of the nodes by selecting the new iscsi target partition on the node. Restore the original data on the new partition.

Use iManager to create a new cluster resource. Now your new resource is configured for clusters.

9. Conclusion:

Using the steps above, you can migrate from a NetWare target to a Linux target.

10. Related links:

AppNote: iFolder on Open Enterprise Server Linux Cluster using iSCSI

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