Step-by-Step Guide for Storage Manager for SANs in Windows Server 2008

Step-by-Step Guide for Storage Manager for SANs in Windows Server 2008

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Microsoft Corporation

Published: February 2008

Abstract
Storage Manager for SANs helps you create and manage logical unit numbers (LUNs) on Fibre Channel and Internet SCSI (iSCSI) disk drive subsystems that support Virtual Disk Service (VDS) in your storage area network (SAN).
This guide provides server and storage subsystem requirements, an introduction to managing LUNs, and step-by-step walkthroughs for creating and assigning LUNs on both Fibre Channel and iSCSI subsystems using Storage Manager for SANs.

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Copyright Information

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All other trademarks are property of their respective owners.

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Contents

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Introduction to Storage Manager for SANs 5

Overview of LUN Management in Storage Manager for SANs 5

Managing LUNs in a Fibre Channel environment 5

Managing LUNs in an iSCSI environment 5

Using Storage Manager for SANs 6

Requirements for Storage Manager for SANs 6

Opening Storage Manager for SANs 7

Managing Storage on a Remote Computer 8

Support for Multipath I/O 9

Deploying LUNs Using Storage Manager for SANs 9

Task 1: Configure Server Connections 11

Task 2: (iSCSI Only) Configure Targets and Enable Portals 12

Task 3: (iSCSI Only) Configure Security 13

Task 4: (iSCSI Only) Establish Logon Sessions Between the Initiator and Targets 15

Task 5: Create a LUN 16

Monitoring the status of LUN creation 18

Providing LUN Access to a Server Cluster 19

Introduction to Storage Manager for SANs

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Storage Manager for SANs is a Microsoft Management Console (MMC) snap-in that helps you create and manage logical unit numbers (LUNs) on Fibre Channel and Internet SCSI (iSCSI) disk drive subsystems that support Virtual Disk Service (VDS) in your storage area network (SAN).
Before you deploy Storage Manager for SANs on a production server, we recommend that you use this guide to first familiarize yourself with the different LUN management options in Storage Manager for SANs by installing and running it on a test server.

Overview of LUN Management in Storage Manager for SANs

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You can use Storage Manager for SANs to create and manage logical unit numbers (LUNs) on both Fibre Channel and Internet SCSI (iSCSI) disk storage subsystems in your storage area network (SAN).
A LUN is a logical reference to a portion of a storage subsystem. A LUN can comprise a disk, a section of a disk, a whole disk array, or a section of a disk array in the subsystem. Using LUNs simplifies the management of storage resources in your SAN because they serve as logical identifiers through which you can assign access and control privileges.
Because of hardware, protocol, and security differences, LUN configuration and management are different in Fibre Channel and iSCSI environments. This section explains those differences.

Managing LUNs in a Fibre Channel environment

In a Fibre Channel environment, LUNs created on a Fibre Channel disk storage subsystem are assigned directly to a server or cluster, which accesses the LUN through one or more Fibre Channel host bus adapter (HBA) ports. You only need to identify the server or cluster that will access the LUN, and then select which HBA ports on that server or cluster will be used for LUN traffic.
When a server or cluster is identified, Storage Manager for SANs will automatically discover the available Fibre Channel HBA ports on that server or cluster. You can also add ports manually by entering their World Wide Name (WWN).

Managing LUNs in an iSCSI environment

Unlike in a Fibre Channel environment, LUNs created on an iSCSI disk storage subsystem are not only assigned to a server or cluster. For iSCSI, LUNs are first assigned to logical entities called targets.
Targets are created in order to manage the connections between an iSCSI device and the servers that need to access it. A target defines the portals (IP addresses) that can be used to connect to the iSCSI device, as well as the security settings (if any) that the iSCSI device requires in order to authenticate the servers requesting access to its resources.Note

In most cases, you can create and manage targets yourself. However, some iSCSI storage subsystems only support simple target configurations, where targets are automatically managed by the subsystem. With simple target configurations, you also cannot delete a target or manually assign LUNs to it. LUNs are automatically assigned when they are created. For this type of subsystem, you just need to identify the server or cluster that will access the LUN, and the iSCSI subsystem will enable access from that server or cluster to the LUN.

To connect to a target, a server in the SAN uses an iSCSI initiator. An iSCSI initiator is a logical entity that enables the server to communicate with the target. The iSCSI initiator first logs on to the target. After access is granted by the target, the server can start reading and writing to all LUNs assigned to that target. Each iSCSI initiator can have one or more network adapters through which communication is established.
As with Fibre Channel environments, you only need to identify the server or cluster that will access the LUN. Storage Manager for SANs automatically discovers the iSCSI initiators on that server or cluster, and lists all the available adapters in those initiators. After the iSCSI adapters have been discovered, you can select which adapters will be used for LUN traffic.
For more information about iSCSI, see http://go.microsoft.com/fwlink/?LinkId=102299.

Using Storage Manager for SANs

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This section provides basic information about the system requirements for Storage Manager for SANs and its storage management features.
In this section:

 Requirements for Storage Manager for SANs

 Opening Storage Manager for SANs

 Managing Storage on a Remote Computer

Requirements for Storage Manager for SANs

To use Storage Manager for SANs, the server and the storage subsystems must meet the following requirements:

 The server must be running Windows Server 2008 with the Storage Manager for SANs feature installed. To add the feature, in Server Manager click the Features node, and then click Add Features to launch the Add Features Wizard.

 The storage subsystems that you want to administer using Storage Manager for SANs must support Virtual Disk Service (VDS). For more information about VDS, see http://go.microsoft.com/fwlink/?linkid=93546.

 The VDS hardware provider for each storage subsystem must be installed on the server.

 The storage subsystems must be directly attached to your server or must be accessible over the network.

 To use Storage Manager for SANs with an Internet SCSI (iSCSI) subsystem, an iSCSI software initiator such as Microsoft iSCSI Initiator must be installed on the server. iSCSI Initiator is available in Administrative Tools in Windows Server 2008. For more information about iSCSI, see http://go.microsoft.com/fwlink/?LinkId=102299.

Opening Storage Manager for SANs

After you install the feature, you can use the Storage Manager for SANs Microsoft Management Console (MMC) snap-in.
You must be a member of the local Administrators group, or equivalent, to use Storage Manager for SANs.To open Storage Manager for SANs

 In Administrative Tools, click Storage Manager for SANs. -Or-  Open Server Manager. a. Expand Roles, expand File Services, and expand Share and Storage Management. b. Click Storage Manager for SANs.

Performing Storage Management Tasks

The following is a list of tasks that you can perform from the three main nodes in Storage Manager for SANs.

LUN Management

 View detailed information about the logical unit numbers (LUNs) on your Fibre Channel and iSCSI storage subsystems.

 Create, rename, extend, delete, assign, and unassign LUNs.

 Add servers or clusters to your storage area network (SAN) and enable host bus adaptor ports and iSCSI initiator adaptors on those servers or clusters.

 Manage targets for iSCSI subsystems: create, remove, configure security settings for, and log on to iSCSI targets.

Subsystems

 View detailed information about the storage subsystems in your SAN that have been discovered by VDS.

 Rename a subsystem.

Drives

 View detailed information about the disk drives in the storage subsystems that have been discovered in your SAN.

 Make a drive light blink.

Managing Storage on a Remote Computer

To manage storage resources on a remote computer, you can connect to the computer from Storage Manager for SANs. While you are connected, the Results pane displays the objects created on the remote computer, which allows you to manage them from MMC.
To manage remote storage resources with Storage Manager for SANs:

 The remote computer must be running Windows Server 2008, and at least one VDS hardware provider must be installed on it.

 The remote computer must be a member of the same domain as the computer you are connecting from.

 Enable the Remote Volume Management firewall exception on both the local computer and the remote computer. This exception can be enabled by using Windows Firewall in Control Panel.

 You must be logged on to the local computer with a domain account that is a member of the Administrators group on the remote computer.To connect to a remote computer from Storage Manager for SANs

1. In Administrative Tools, click Storage Manager for SANs. 2. In the console tree, right-click Storage Manager for SANs, and then click Connect to another computer. 3. In the Connect to Another Computer dialog box, click Another computer. Then type the name of the computer that you want to connect to (or click Browse to search for a remote computer). 4. Click OK.

Support for Multipath I/O

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Multipath I/O (MPIO) is a feature that provides support for using multiple data paths to a storage device. Multipathing increases availability by providing multiple paths (path failover) from a server or cluster to a storage subsystem.
You must install MPIO if you will be enabling more than one read/write path from a server to a logical unit number (LUN) by assigning multiple Fibre Channel ports or multiple Internet SCSI (iSCSI) initiator adapters on that server to the same LUN.
To install the MPIO feature, in Server Manager click the Features node, and then click Add Features to start the Add Features Wizard.Caution

To prevent data loss, ensure that the server supports MPIO before you enable multiple Fibre Channel ports or iSCSI initiator adapters for LUN access. If the server does not support MPIO, or if you are not sure, enable only a single Fibre Channel port or iSCSI initiator adapter.Caution

if you will be enabling access to a LUN from a cluster, ensure that Failover Clustering has been properly installed on each server in the cluster, or data loss can occur. For more information about installing Failover Clustering, see http://go.microsoft.com/fwlink/?LinkId=86168.

For more information about MPIO, see http://go.microsoft.com/fwlink/?LinkId=81020.

Deploying LUNs Using Storage Manager for SANs

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This section walks you through the tasks involved in using Storage Manager for SANs to deploy logical unit numbers (LUNs) on both Fibre Channel and Internet SCSI (iSCSI) subsystems. Figure 1 shows the process for deploying LUNs on both types of subsystems.
Figure 1   LUN Deployment Process in Storage Manager for SANs

If the LUNs will be deployed on a Fibre Channel subsystem, you only need to identify the servers that will access the LUNs, select which host bus adapter (HBA) ports on those servers will be used for LUN traffic, and finally create and assign LUNs directly to the servers.
If the LUNs will be deployed on an iSCSI subsystem, the process requires additional steps. After identifying the servers that will access the LUNs and selecting the iSCSI initiator adapters that will be used for LUN traffic, you should do the following:

1. Create and configure targets on the iSCSI subsystems and enable portals on those targets to handle LUN I/O traffic.

2. Optionally configure iSCSI security.

3. Establish logon sessions from the iSCSI initiator on each server to one or more targets.

4. Finally, create LUNs and assign them to the targets.

Before you create a LUN on either type of storage subsystem, verify the following:

 The storage subsystem is listed at the Subsystems node.

 There is storage space available on the storage subsystem, and the LUN type you want to create is supported by the subsystem.

 If you want to assign the LUN to a cluster, the cluster has been fully configured by installing Failover Clustering.Caution

To prevent data loss, make sure that each server is a member of only one cluster and that Failover Clustering has been installed on each server in the cluster. For more information about installing Failover Clustering, see http://go.microsoft.com/fwlink/?LinkId=86168.

 If the server you will be assigning the LUN to will access the LUN through more than one Fibre Channel port or iSCSI initiator, Multipath I/O has been installed and is running on that server.Caution

Data loss can occur if you assign the LUN to a server that does not have Multipath I/O installed and will access the LUN through more than one Fibre Channel port or iSCSI initiator. For more information, see Support for Multipath I/O.

In this section:

 Task 1: Configure Server Connections

 Task 2: (iSCSI Only) Configure Targets and Enable Portals

 Task 3: (iSCSI Only) Configure Security

 Task 4: (iSCSI Only) Establish Logon Sessions Between the Initiator and Targets

 Task 5: Create a LUN

Task 1: Configure Server Connections

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The first task in deploying logical unit numbers (LUNs) is to configure the connections that servers in your storage area network (SAN) will use to access the LUNs that you create on your storage subsystems.
Storage Manager for SANs automatically discovers Fibre Channel ports and Internet SCSI (iSCSI) initiator adapters on a server. You only need to identify the server that will access the LUN, and then select which ports and/or initiator adapters on that server will be enabled for LUN access. Note

Fibre Channel ports can also be added manually by entering their World Wide Name (WWN).To configure server connections

1. In the console tree, click LUN Management. 2. In the Actions pane, click Manage Servers Connections. 3. To add a server: a. In the Manage Server Connections dialog box, click Add. b. In the Add Server dialog box, type the name or browse to the server that you want to add and optionally, type a description for it. c. Click OK. The server will now be listed in the Manage Server Connections dialog box. 4. To configure the Fibre Channel ports on a server: a. In the Manage Server Connections dialog box, select a server from the server list. The Fibre Channel Ports tab lists all of the host bus adapter (HBA) ports that are available on the selected server. b. If you want to manually enter a new port, on the Fibre Channel Ports tab, click Add and enter the WWN of the new port. Optionally, type a description for the new port. c. To enable a port, select its check box in the Enable column.Caution If you enable more than one Fibre Channel port and the server is not configured to use Multipath I/O, data corruption can occur. For more information about Multipath I/O, see Support for Multipath I/O earlier in this guide. d. After selecting all ports that you want to enable, click OK.Note If you create LUNs only on a Fibre Channel subsystem, no additional configuration is needed before creating LUNs. You can skip to Task 5: Create a LUN later in this guide. 5. To configure the iSCSI initiator adapters on a server: a. In the Manage Server Connections dialog box, select a server from the server list. The iSCSI Initiator Adapters tab lists all the initiator adapters that are available on the selected server. b. To enable an initiator adapter, select its check box in the Enable column. Caution If you enable more than one iSCSI initiator adapter and the server is not configured to use Multipath I/O, data corruption can occur. For more information about Multipath I/O, see Support for Multipath I/O earlier in this guide. c. After selecting all initiator adapters that you want to enable, click OK.

Task 2: (iSCSI Only) Configure Targets and Enable Portals

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Targets are created in order to manage the connections between the Internet SCSI (iSCSI) storage subsystems in your storage area network (SAN) and the servers that need to access them. You assign logical unit numbers (LUNs) to a target, and all servers that log on to that target will have access to the LUNs assigned to it.
When you configure a target, you select the portals (network connections) that the target will provide for LUN access.Note

In most cases, you can create and manage targets yourself. However, some iSCSI storage subsystems only support simple target configurations, where targets are automatically created when you create a LUN. With simple target configurations, you also cannot delete a target or manually assign LUNs to it. LUNs are automatically assigned when they are created. For this type of subsystem, you just need to identify the server or cluster that will access the LUN, and the iSCSI subsystem will enable access from that server or cluster to the LUN.To configure a target on an iSCSI storage subsystem

1. In the console tree, click LUN Management, 2. In the Actions pane, click Manage iSCSI Targets. 3. In the Manage iSCSI Targets dialog box, in Select a subsystem to manage, select the iSCSI storage subsystem you want to configure a target for, and then click Add. 4. In the Add Target dialog box, in Target Friendly Name, type a descriptive name for the target that will help you to distinguish it from other targets. A separate iSCSI name will be automatically assigned. 5. In Select portals to enable for this target, select the check box next to each IP address that the target should use, and then click OK. The Manage iSCSI Targets dialog box shows the new target, with the portals that you enabled listed at the bottom. 6. If you want to configure more targets, go back to step 3. 7. When you are finished configuring targets, click Close.

Task 3: (iSCSI Only) Configure Security

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There are several levels of Internet SCSI (iSCSI) security available with Storage Manager for SANs. The basic level is based on the Challenge Handshake Authentication Protocol (CHAP). CHAP is a protocol that is used to authenticate the peer of a connection and is based upon the peers sharing a secret (a security key that is similar to a password). IP security (IPsec) is a protocol that enforces authentication and data encryption at the IP packet layer, which provides an added level of security.
You must choose the security level that best fits the security policies of your organization:

 One-way CHAP authentication. With this level of security, only the target authenticates the initiator. The secret is set just for the target and all initiators that want to access that target need to use the same secret to start a logon session with the target.

 Mutual CHAP authentication. With this level of security, the target and the initiator authenticate each other. A separate secret is set for each target and for each initiator in the storage area network (SAN).

 IPsec. With this level of security, all IP packets sent during data transfers are encrypted and authenticated. A common key is set on all IP portals, allowing all peers to authenticate each other and negotiate packet encryption. For more information about IPsec, see http://go.microsoft.com/fwlink/?linkid=93520. Caution

At a minimum, use one-way CHAP authentication between iSCSI initiators and targets.Note

The level of security that you can set for a storage subsystem depends on the hardware manufacturer. Not all subsystems support all levels of iSCSI security. You should contact your hardware manufacturer to verify what level of security is supported.

For more information about iSCSI, see http://go.microsoft.com/fwlink/?LinkId=102299.To configure iSCSI security

1. In the console tree, click LUN Management. 2. In the Actions pane, click Manage iSCSI Security. 3. To configure one-way CHAP authentication, in the Manage iSCSI Security dialog box, configure the following settings on the Targets tab: a. If you want to configure different CHAP secrets for different targets, in the list of targets, select a target that you want to set the CHAP secret for, and click Set Secret. -Or- To use the same CHAP secret for a group of targets, select the targets from the list and click Set Secret. b. In the Set Secret dialog box, type and confirm the target CHAP secret. c. Optionally, select Remember secret on local initiator if you want to automatically pass the new secret to the local initiator. d. To set the new secret, click OK. 4. To configure mutual CHAP authentication, you must first configure one-way CHAP authentication by following step 3. Then, enter the following configuration on the Local Initiator tab: a. Type and confirm the CHAP secret for the local initiator. b. Under mutual CHAP authentication, the initiator will only be able to log on to targets that share the initiator secret. To share the initiator secret with the targets that the server needs to access, in the list of targets, select each target that you want to authenticate on the initiator. c. To set the new secret for the local initiator and to share it with the selected targets, click Apply Secret. 5. To configure IPsec, in the Manage iSCSI Security dialog box, configure the following settings on the Portals tab: a. If you want to use different IPsec keys for different portals, in the list of portals, select a portal and click Set IPsec Key. -Or- To use the same IPsec key for a group of portals, select the portals from the list, and click Set IPsec Key. b. In the Set IPsec Key dialog box, type and confirm a new IPsec key. c. Optionally, select Remember the IPsec key on local initiator if you want to automatically pass the new key to the local initiator. d. To set the new IPsec key, click OK. 6. When you are done configuring iSCSI security, click Close.

Task 4: (iSCSI Only) Establish Logon Sessions Between the Initiator and Targets

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For a server to access logical unit numbers (LUNs) that are assigned to a target on an Internet SCSI (iSCSI) subsystem, the server initiator must first establish a session with the target through an iSCSI logon process.
You can log on to iSCSI targets using Storage Manager for SANs. This starts a logon session only between the server that is running Storage Manager for SANs and the selected target. Each server that requires access to the LUNs that are assigned to a target must start a separate logon session with that target.Note

If you have not yet configured iSCSI security for initiators and targets, you will not be able to log on to a target. For more information about iSCSI security, see Task 3: (iSCSI Only) Configure Security.Note

You can also start a logon session between a server in your storage area network (SAN) and a target, using the local iSCSI initiator user interface, if available (this depends on the iSCSI initiator software that is installed on that server).

When you log on to a target, you can select the type of Challenge Handshake Authentication Protocol (CHAP) authentication to use during the session. If you have set an IPsec key for the portals, data encryption is automatic. To establish logon sessions between the initiator and iSCSI targets

1. In the console tree, click LUN Management. 2. In the Actions pane, click Log On to iSCSI Targets. 3. In the Log On to iSCSI Targets dialog box, select the target that you want to establish a logon session with, and click Log On.Note If the target that you want to log on to is not listed, click Close. Then, in the Actions pane, click Refresh, and when the refresh has completed, start over from step 2. 4. In the Log On to Target dialog box, select the type of CHAP authentication to use for the logon session:  Log on using one-way CHAP authentication  Log on using mutual CHAP authentication 5. To establish the logon session, click OK.

Task 5: Create a LUN

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After you complete tasks 1 through 4, you can use the Provision Storage Wizard to create a logical unit number (LUN) on a Fibre Channel or Internet SCSI (iSCSI) storage subsystem. With the wizard you can optionally assign the LUN to your server or another server or cluster, create a volume on the LUN, and format the volume.
If you create a LUN but do not use the wizard to create a volume on it immediately, you can use Disk Management to create the volume later. In this case the disk associated with that LUN will be visible to any server or cluster that you assign it to, but it will be offline. Before you can create a partition or volume on that disk, you must use DiskPart or Disk Management to bring the disk online. For more information about how to bring a disk online, see:

 Disk Management (http://go.microsoft.com/fwlink/?LinkID=93544)

 Online command in DiskPart (http://go.microsoft.com/fwlink/?LinkId=93451) To create a LUN

1. In the console tree, click LUN Management. 2. In the Actions pane, click Create LUN. 3. Follow the steps in the Provision Storage Wizard, providing the information described in Table 1.

The following table contains some general recommendations and information about each one of the pages in the Provision Storage Wizard:
Table 1   Completing the Provision Storage Wizard

Wizard Page	Details
Before You Begin	Verify that storage is available on the subsystem and, if you want to use the wizard to assign the LUN to a server, the storage area network (SAN) server connections have been configured.
Storage Subsystem and Type	Select the subsystem on which to create the LUN. The list of subsystems specifies the total capacity of each available subsystem, the type of subsystem (Fibre Channel or iSCSI), and the percentage of free space.
LUN Type	Specify the LUN type to create:  The list of LUN types includes each LUN type that is available on the selected subsystem and specifies the maximum-size LUN for each type.  Fault tolerant LUN types require more disk space than simple LUNs. Therefore, the maximum size of the LUN is smaller than for a simple LUN.
LUN Name and Size	Type a name for the new LUN and specify the size of the LUN:  The LUN name can have as many as 63 characters.  Depending on the version of the Virtual Disk Service (VDS) provider that the subsystem is running, you may not be able to type a name for the LUN.  Type the LUN size and click the drop-down list to select between megabytes (MB), gigabytes (GB) and terabytes (TB).
iSCSI Target (iSCSI only)	If iSCSI targets have already been created on the subsystem, you can assign the LUN to one of those targets now. You can also leave it unassigned for later use.
Server Assignment	Choose to assign the LUN to a server or cluster. You can also choose to leave it unassigned for later use.
Server Access (Fibre Channel only)	If you chose to assign the LUN and you have already configured your server connections, you can select the server or server cluster the LUN will be assigned to.
Volume Creation	If you chose to assign the LUN to the server you are currently managing with the Storage Manager for SANs snap-in, you can create an NTFS volume for the LUN.
Format	If you select to format the volume:  As a general rule, leave the Allocation unit size option as Default. The allocation unit size is the smallest amount of disk space that can be allocated to hold a file. Windows selects default sizes based on the size of the volume. These default sizes are selected to reduce the amount of space that is lost and the amount of fragmentation on the volume.  The Quick Format option speeds the volume creation process on large LUNs. If you want to scan for bad sectors during the formatting process, clear the check box for this option and a full file format will be done.Note If you prefer, you can select not to format the volume and can use Disk Management to format it later. For more information about Disk Management, see http://go.microsoft.com/fwlink/?LinkId=93544.
Review Settings and Create Storage	Before creating the LUN, the wizard lists all the properties that you have selected for the new LUN. Click Create to start the LUN creation process.

Monitoring the status of LUN creation

The process of creating a LUN can take minutes or hours, depending on the size of the LUN. Do not close Storage Manager for SANs while a LUN is being created. If the session ends before the process completes, you might not be able to determine the completion status for the LUN.
To monitor the status of the LUN while it is being created, in the LUN Management node, refer to the Task Status column on the results pane. While the LUN is being created, the column shows the percentage of the LUN that has been completed. When the operation has finished successfully, the task status changes to Created.
If LUN creation fails, you can click the LUN entry in the Results pane to display failure information in the description area below it.

Providing LUN Access to a Server Cluster

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With Storage Manager for SANs, you can provide logical unit number (LUN) access to a group of servers (a server cluster) in your storage area network (SAN). You create server clusters by defining them in Storage Manager for SANs and by installing Failover Clustering on each individual server that will be part of the cluster.Caution

To prevent data loss, make sure that each server is a member of only one cluster and that Failover Clustering has been installed on each server in the cluster. For more information about installing Failover Clustering, see http://go.microsoft.com/fwlink/?LinkId=86168.To provide LUN access to a server cluster

1. In the console tree, click LUN Management. 2. In the Actions pane, click Manage Server Connections. 3. In the Manage Server Connections dialog box, click Manage Clusters. 4. In the Manage Clusters dialog box, click Add. 5. In the Add New Cluster dialog box, type a name for the cluster and optionally, type a general description that will help you identify the cluster. 6. From the server list, select all the servers that you want to include in the new cluster.Note To add servers to a cluster, you must first add them to the server list in Manage Server Connections. For more information, see Task 1: Configure Server Connections earlier in this guide. 7. Click OK to create the new cluster. 8. Click OK again to go back to the Manage Server Connections dialog box. The new cluster will now be listed in the Manage Server Connections dialog box. 9. To configure the connections of the cluster, configure the Fibre Channel ports or the Internet SCSI (iSCSI) initiator adapters of each individual server included in the cluster by selecting the server from the list. All of the configuration changes you make on the individual servers will take effect on the cluster. 10. After server clusters are created, LUNs can be assigned to them in the same way they are assigned to individual servers.Caution If you are going to enable more than one connection (Fibre Channel ports and/or iSCSI initiator adapters) on a server in the cluster, and that server is not configured to use Multipath I/O, data corruption can occur. For more information about Multipath I/O, see Support for Multipath I/O earlier in this guide.