Managing the iSCSI Target Server

The iSCSI target server in Windows Server 2012 can be managed by using the user interface through Server Manager, as seen in earlier chapters, or PowerShell cmdlets. This section also walks through the Best Practice Analyzer (BPA) and the options with System Center. With System Center 2012 Virtual Machine Manager, storage arrays also can be managed using an SMI-S provider.

Storage Providers

Windows Server 2012 has two features related to the iSCSI target server:

  • Volume Shadow Copy Service (VSS)
  • Virtual Disk Service (VDS)

VSS is a framework that allows a volume backup to be performed while the application continues with I/Os. VSS coordinates among the backup application (requester), applications such as Hyper-V (writer), and the storage system such as the iSCSI target (provider) to complete the application-consistent snapshot.

The iSCSI target VSS hardware provider communicates with the iSCSI target server during the VSS snapshot process, thus ensuring that the snapshot is application consistent.

The VDSmanages a wide range of storage configurations. In the context of an iSCSI target, it allows storage management applications to manage iSCSI target servers. In previous versions of Windows Server, the Storage Manager for SANs could be used for storage management tasks. In Windows Server 2012, this console snap-in was removed and replaced by Server Manager, PowerShell/WMI, and Storage Management Initiative Specification (SMI-S). Such an SMI-S provider for the iSCSI target will be made available together with System Center 2012 SP1, which is covered in the next section.

These storage providers are typically installed on a different server than the one running iSCSI target server—for example, a virtual guest cluster running Exchange Server. If this guest is not running Windows Server 2012, you will need to download and install the down-level storage providers:

www.microsoft.com/en-us/download/details.aspx?id=34759

iSCSI Target SMI-S Provider

In Windows Server 2012, the management of the storage device, the iSCSI Software Target, can be done using a SMI-S provider. An SMI-S provider is a software component for a particular storage product. It implements an HTTP/HTTPS server, parses XML requests, and knows how to control those specific devices that usually have their own unique management interfaces.

With the release of SP1 for System Center 2012 Virtual Machine Manager (VMM), the iSCSI target server becomes its own SMI-S provider. The provider follows an embedded provider model, which means the component is installed directly on the iSCSI target server. Figure 6-8 shows how the components interact.The SMI-S provider manages the iSCSI target server by using the iSCSI target WMI provider.

Figure 6-8 SMI-S architecture

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Microsoft has published an interesting blog article, “Introduction to SMI-S,” with additional information on SMI-S. You can access the article here:

http://blogs.technet.com/b/filecab/archive/2012/06/25/introduction-to-smi-s.aspx

As mentioned before, the iSCSI target server role service must first be installed before the provider can be installed, which means the provider will be installed directly on the iSCSI target server. Therefore, make sure this service role is installed before starting the installation. Also make sure Microsoft KB 276147 is installed on this host to improve the performance of the discovery later on.

To start the installation of the SMI-S provider, locate the installation binaries iSCSITargetSMISProvider.msi under one of the following locations:

  • SCVMM installation media: amd64SetupmsiiSCSITargetProv
  • SCVMM installation directory: C:Program FilesMicrosoft System Center 2012Virtual Machine ManagersetupmsiiSCSITargetProv

Follow these instructions to install the SMI-S provider on one of the iSCSI target server(s):

1. From the VMM installation media, navigate to amd64SetupmsiiSCSITargetProv and execute.
2. Read the Welcome Page and then click Next.
3. Accept the License Terms. Click Next.
4. Click the Install button to start the installation process.
5. Click the Finish button to close the window.

Finally, the iSCSI Software Target SMI-S provider can be presented to VMM by running the following PowerShell cmdlets on the VMM management server.

First we need to create a RunAs account to authenticate against the iSCSI target server:

$RunAsCredentials = Get-Credential

$RunAsAccount = New-SCRunAsAccount -Name "<iSCSITargetAdmin>" `
-Credential $RunAsCredentials

The SMI-S provider then can be added as follows:

Add-SCStorageProvider -Name "Microsoft iSCSI Target Provider" `
-RunAsAccount $RunAsAccount -ComputerName “<iSCSITargetComputer>” `
–AddSmisWmiProvider

The Microsoft iSCSI Software Target will then be available in VMM for further management, as illustrated in Figure 6-9.

Figure 6-9 iSCSI target server in VMM

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To provision LUNs by using SCVMM, only two more steps are required. In the SCVMM admin console, perform the following steps:

1. In the Fabric view, navigate to Arrays.
2. Open the Properties of the newly added iSCSI target server.
3. Under the Storage Pools tab, select the appropriate storage pools, assign a Classification, and Click OK (see Figure 6-10).

Figure 6-10 Storage pools in SCVMM

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VMM can now create LUNs and assign them to the Hyper-V hosts. Additional information on how SCVMM discovers, classifies, and provisions remote storage can be found on TechNet:

http://technet.microsoft.com/en-us/library/gg610600.aspx

Note that this version of the SMI-S provider for the iSCSI target server supports only the integration with SCVMM.

Best Practice Analyzer

Microsoft defines guidelines, recommended practices, for configuring Windows Server 2012 that are considered as ideal under normal circumstances. So, wouldn’t it be great to adopt these best practices and incorporate them into the product to give administrators instant feedback on their configuration? Nothing simpler than that…

Windows Server includes a Best Practice Analyzer (BPA), which can be used by an administrator to check whether a server role runs with the recommended configuration by Microsoft. Deviations from this recommended practice, even critical ones, are highlighted for further investigation—note that not all findings are necessarily problematic, as BPA matches the live configuration against a rule set it receives and updates regularly from Microsoft Update. Running the BPA regularly is a good idea to gain an understanding of how close the configuration is to Microsoft’s recommendation—and to understand how and why deviations in your own configuration happen. Findings marked as critical can then be evaluated and resolved, minimizing the risk of configurations that result in poor performance or reliability, security risks, or data loss.

A best practice scan can be started in Server Manager for the whole File Services role, including the iSCSI target:

1. In Server Manager, click Local Server.
2. Scroll down to Best Practice Analyzer.
3. Under Tasks, select Start BPA Scan. The scan starts.

The results will be displayed in the same view with a related problem statement and description.

Alternatively, you can use PowerShell to scan a specific model—for example, the iSCSI Target BPA model. To get an overview of all available modules, just use the following cmdlet:

Get-BpaModel | Format-Table -Property Id

The best practice scan is started using the Invoke- cmdlet:

Invoke-BpaModel -ModelId Microsoft/Windows/FileServices

PowerShell

As the iSCSI target management user interface focuses on the presentation of enabling end-to-end scenarios, the underlying cmdlets provide the logic for management tasks that the user interface relies on. The PowerShell capabilities used in the previous version of Windows Server have been expanded for the 2012 release to include the following features:

  • Disk snapshot management
  • Differencing disk management
  • Server global setting management
  • Additional filters

The metadata for the iSCSI target server PowerShell modules are stored in MicrosoftiSCSITarget.psd1.

PowerShell scripts that have been developed using the previous release are not guaranteed to work with Windows Server 2012. Although cmdlet names remain valid, required parameters and their input format might have changed. We suggest explicit testing of existing scripts prior to production use with Windows Server 2012.

To get a list of the new available iSCSI Initiator cmdlets, you can use the Get-Command -Module iSCSI command in PowerShell. For the iSCSI target, the command would be Get-Command-Module IscsiTarget. You can always get detailed help within PowerShell, including a list of parameters for a specific cmdlet, by using Get-Help. For instance, if you want help creating a new iSCSI target portal, you can obtain help by using the following PowerShell command: Get-Help New-IscsiTargetPortal.

Windows PowerShell 3 also introduces a new cmdlet called Show-Command, which opens a graphical user interface leveraging the Windows PowerShell ISE. This capability makes it easy to understand available parameters and cmdlet syntax. The syntax of New-IscsiTargetPortal, for example, can be displayed by typing Show-Command New-IscsiTargetPortal in a PowerShell console, which opens the dialog box shown in Figure 6-11.

Figure 6-11 PowerShell Show-Command

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Quite a few cmdlets have already been shown at the beginning of this chapter. Did you know that you also could use PowerShell to configure the provide disk? Have a look at this example:

1. Check whether the new disk is available from the operating system: 
Get-Disk
2. You should see a new disk with the friendly name MSFT Virtual HD SCSI Disk Device and an operational status of Offline. You now can bring the disk online by using the appropriate number: 
Set-Disk -Number 1 -IsOffline 0
3. The status of the disk changes to Online. In the next step, you have to make it writeable: 
Set-Disk -Number 1 -IsReadOnly 0
4. Then you can initialize it (MBR or GPT partition style): 
Initialize-Disk -Number 1 -PartitionStyle MBR
5. Finally, you can create a new partition on this disk by using the maximum size, for example: 
New-Partition -DiskNumber 1 -UseMaximumSize
6. To avoid pop-ups from Windows Explorer, you can skip to assigning a drive letter by using -AssignDriveLetter:$False. This step, however, is optional.
7. Finally, you can format the volume and assign a drive letter: 
Get-Partition –DiskNumber 1 | Format-Volume
8. If you need to assign a drive letter, you can just run the following command. Note that Cluster Shared Volumes (CSV) or Cluster Quorum disks do not require a drive letter. 
Get-Partition –DiskNumber 1 | Add-PartitionAccessPath -AccessPath D:
9. Of course, the very well-known diskpart.exe can still be used and would be the preferred tool for previous Windows Server releases.
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