Windows 2003 native mpio

MPIO allows for devices from different storage vendors to coexist, and be connected to the same Windows Server based system. The first DSM to claim ownership of the device is associated with that device and the remaining DSMs are not allowed a chance to press claims for that already claimed device. If the DSM does support the device, it then indicates whether the device is a new installation, or is the same device previously installed but is now visible through a new path.

In case of a failover, the DSM determines what new path should be used. The Microsoft device-specific module DSM provided as part of the complete solution in Windows Server includes support for the following policy settings:. The control panel can be used to do the following:. You can list the VID and PID for storage that is already connected to the server by using the mpclaim tool at the command prompt.

Discover Multi-Paths Use this tab to run an algorithm for every device instance that is present on the system and determines if multiple instances actually represent the same Logical Unit Number LUN through different paths.

We recommend using vendor installation software to install the vendor's DSM. The report includes information on the device-specific module DSM that is being used, the number of paths, and the path state. You can also save this configuration at a command prompt by using the mpclaim command. EXE Usage examples. Before you can configure the load-balancing policy setting by using Disk Management, the device must first be claimed by MPIO. If Path A fails, Path B is used. Select the Preferred check box, and then click OK.

For a complete list of available PowerShell cmdlets in the Storage module, including usage and examples, please refer to the following TechNet site:. You can also obtain help for individual commands by specifying the cmdlet with Get-Help, such as shown below:. In Windows 8, PowerShell modules which ship with Windows do not include help content "inbox" instead this content is provided on the Internet, and may be updated via PowerShell from a computer which has Internet access.

Once a PowerShell module has been imported into the current PowerShell session, the help content may be downloaded and updated via the following command:. Note: the —Force parameter must be used if attempting to update more than once per 24 hour period.

For example, in order to obtain script examples for the Get-Disk cmdlet, the following command is utilized:. Tip: If these steps are performed prior to connecting devices of the desired BusType, you can typically avoid the need for a restart. In most cases, the default values may be adequate; however, it may be necessary to adjust these settings to obtain optimal performance for your environment.

Scenario 1 A two-node Windows Server failover cluster is configured with multiple connections to storage for each node by using MPIO, and employs multiple active paths to maximize throughput.

Due to application Service Level Agreement SLA requirements, in the event of path failures, short timeout values are required by the customer so that the resources will failover to the other cluster node more quickly.

In this case, timer values such as the PDORemovePeriod are set to a low value and then tested to ensure compliance with customer requirements.

Scenario 2 A single server that is not configured as a failover cluster is configured with MPIO and multiple connections to storage to provide both increased throughput and fault tolerance of path failures. In this case, timers such as PDORemovePeriod are increased to allow additional time for path recovery to occur.

For any customer scenario, determining the best timer values to use depends on a number of different variables, such as any of the following, which could all potentially impact whether the current settings would meet SLA or Operating Level Agreement OLA requirements:. Settings 1 through 5 in the following table can be set through the user interface. The information provided on these settings is specific to the use of Microsoft DSMs. When using a vendor-provided DSM, refer to vendor documentation for information about the recommended timer values.

Although it is possible to set the following values to a very large number, we recommend that you use caution when doing so, and that you test the values for applicability prior to using them in a production environment. If this value were applied to a setting such as PDORemovePeriod where it represents seconds , the value would equate to approximately 49, days of delay before an error would be reported. Type is Boolean and must be filled with either 0 disable or 1 enable.

By default, it is disabled. This setting is used to indicate the time period in seconds with which MPIO has been requested to perform path verification. This setting controls the amount of time in seconds that the multipath pseudo-LUN will continue to remain in system memory, even after losing all paths to the device.

The default setting is 3. Represents the period after which PathRecovery is attempted. The end result is that the system now has at least one path and one device online, but no pseudo-LUN to represent that device.

MPIO has a path recovery mechanism that can be used to avoid this issue. However, by default, the period at which path recovery is attempted is set to twice in the PDORemovePeriod. In the majority of cases, the default is acceptable, but it does not solve the problem in this particular scenario. This is where the settings listed in the previous tables come into play. They allow you to configure the timer that determines the period at which path recovery attempts are done.

This interval causes path recovery to be attempted every 30 seconds. Caution is advised when setting the PathRecoveryInterval to small values. By decreasing this value, larger amounts of path verification traffic are generated.

This traffic increases with the number of LUNs available on the host, and the smaller the value. The following command, mpclaim. To change the load-balancing policy setting to Least Blocks for all disks that are claimed by Microsoft DSM, use the following command: mpclaim. To clear the load-balancing policy settings for all disks claimed by Microsoft DSM and reset to the default, use the following command:.

Note that the vendor string length is 8 characters, the product string length is 16 characters, and both fields are padded with spaces as needed. Add MPIO support for all devices that are enterprise storage devices. The tool analyzes all devices that are seen by the system, determines if there are multiple paths to the device, and if there are, adds MPIO support for them.

Note that the vendor string length is 8 characters, and the product string length is 16 characters. The tool removes MPIO support for all devices on the system, even if multiple paths do not exist to the array. This command also displays the associated Vendor ID and Product ID required to add or remove support for the given device. To use mpclaim , you must be running cmd. For a list of all hardware IDs for all currently attached devices, open a command prompt, and then type mpclaim —E.

EXE —H. This ID is not used to control the management of any disk devices. If a disk is presented on a given logical path, all disks presented on that path need to also be presented on all logical paths that contain any subset of those disks.

Physical paths correspond to the actual physical hardware over which the logical paths are hosted. See the Installing Multipath-IO section for more details. These steps work for Windows Server , R2, , and The only differences between the graphical user interface is the changes in the dialogs visual appearances. The example provided in this section are taken from Windows Server No 3rd party DSMs are supported.

A Reboot Required dialog box will be displayed after completing this configuration. Choose Yes or No depending on what other management or application tasks you are performing, but keep in mind that a reboot is required for the new MPIO Devices settings to take effect. If iSCSI connectivity is being used, you may ignore this reboot requirement. The reason for this is to reduce the number of reboot cycles for the Windows Server host since adding iSCSI support requires an additional reboot.

Click OK. You will be prompted to perform a reboot at this time. The reason for preferring PowerShell is the requirements of ensuring the device that is added adheres to the string formatting of Vendor 8 characters and Product 16 characters. Note that if using iSCSI, please confirm that the additional adapter is present. Removing the default MPIO device is not necessary but simply a recommendation as the default Vendor 8 Product 16 device does not do anything.

The final step to perform using PowerShell is to reboot the computer. Good job! We would have to buy a license for it. I can see all the disks now. Is there any issue moving forward without it? It's important to have some kind of path management software so your LUNs have redundant paths as well as additional bandwidth. Dear Aubrey - that's great! Thanks for sharing so others could find the solution as well.

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For more information, visit Hitachi Cookies Policy. Terms of Use Privacy Policy Legal. Hitachi Vantara Customer. Sign in to ask the community. View This Post. Edited 15 August at Let me know if you have any suggestions.