Dell EMC SC Series Storage and Microsoft Multipath I/O Abstract This document provides an overview of Microsoft® Multipath I/O (MPIO) along with best practice guidelines for configuring MPIO on Microsoft Windows Server® with Dell EMC™ SC Series storage.
Revisions Revisions Date Description October 2010 Initial release October 2010 Corrected errors November 2011 Additional content on Microsoft® Windows Server® Core October 2012 Updated to include Windows Server 2012 content May 2013 Updated to include Windows Server 2008 R2/2012 iSCSI initiator setup and appendix listing recommended hotfixes and registry values October 2013 Updated to include Windows Server 2012 R2 content January 2014 Updated hotfix information January 2015 Updated config
Table of contents Table of contents Revisions.............................................................................................................................................................................2 Acknowledgements .............................................................................................................................................................2 Table of contents .................................................................................................
Table of contents 5.3.1 Using the disk management GUI:.....................................................................................................................23 5.3.2 Using the MPCLAIM command ........................................................................................................................24 A B 4 Windows Server single-path and MPIO configuration recommendations for SC Series storage ..............................26 A.
Preface 1 Preface This document provides an overview of Microsoft® Multipath I/O (MPIO) along with best practice guidelines for configuring MPIO on Microsoft Windows Server® 2008 R2, 2012, 2012 R2, and 2016 with Dell EMC™ SC Series storage. Nano Server was an installation option (in addition to Core and Desktop) offered for the first time with Windows Server 2016. Nano Server was originally designed to run as a base OS on physical or virtual servers.
Introduction to Microsoft Multipath I/O 2 Introduction to Microsoft Multipath I/O Microsoft MPIO is a framework that allows administrators to configure load balancing and failover processes for Fibre Channel (FC), iSCSI, and serial attached SCSI (SAS) front-end (FE) connected storage devices. Load balancing can be configured to use up to 32 independent paths for each connected storage device. Two to four paths per storage device is a common configuration with SC Series storage.
Introduction to Microsoft Multipath I/O 1 8 4 2 8 4 2 PORT 1 PCIe x8 8Gb FC Server PORT 2 Figure 1 shows an example cable configuration using legacy port mode. Each color represents a separate fault domain.
Introduction to Microsoft Multipath I/O 1 8 4 2 PORT 2 8 4 2 PCIe x8 8Gb FC Server PORT 1 A virtual front-end port configuration with iSCSI fault domains (FD 1 and FD 2 in Figure 3) is similar to FC.
Introduction to Microsoft Multipath I/O 2.1.3 SAS front-end support Select SC Series arrays support SAS front-end (FE) ports for MPIO connectivity. With SAS FE, host servers are connected directly to SAS ports on the SC Series array as shown in Figure 4. Host servers require a supported SAS host bus adapter (HBA) to connect directly to SC Series SAS FE ports.
Install the MPIO feature 3 Install the MPIO feature Microsoft includes a built-in DSM for Windows Server 2008 and newer that manages all aspects of failover and load balancing. SC Series storage uses this DSM because it provides all necessary functionality. This also simplifies implementation as it eliminates the need to install and maintain another software component in the environment. The Microsoft DSM is not functional on Windows Server until the MPIO feature is installed.
Install the MPIO feature 3.2 Windows Server 2012 or later The MPIO feature can be installed on Windows Server 2012 or later using the Server Manager GUI or through the MPIO module in Microsoft PowerShell®. On Windows Server 2012 and newer Core installations, use PowerShell to install MPIO. 3.2.1 Server Manager GUI 1. 2. 3. 4. 5. 6. 7. Open Server Manager. From the Dashboard, click Add Roles and Features. When the wizard opens, click Next.
Configure server objects on SC Series storage 4 Configure server objects on SC Series storage Follow the steps in this section to configure Windows Server objects on SC Series storage. These steps assume a properly configured SC Series array with front-end cabling in place for FC, iSCSI, or SAS FE, with at least two paths available to support MPIO. • • • FC: Ensure that proper zoning and cabling is in place to allow the host server HBAs to see the SC Series HBAs.
Configure server objects on SC Series storage 3. Review the prerequisites and click Next. 4. If more than one SC Series array is available, select the desired array and click Next. 5. The wizard will gather information about the host which may require a few minutes. If issues are encountered with the discovery, resolve them and repeat the process. 6. Once the server object is created, create and map at least one SC Series volume to the server. 7. Configure the MPIO settings (see section 5). 4.
Configure server objects on SC Series storage 4. For each HBA, perform Scan Fibre Devices. The HBA will scan the fabric looking for storage devices. Although none will be found at this point, this advertises the presence of the HBA WWN to the SC Series array so that the WWN is visible. 14 5. 6. 7. 8. Log in to the desired SC Series array using the Dell Storage Manager client. Under Hardware, expand the Servers folder to the desired location. Right-click the desired folder and select Create Server.
Configure server objects on SC Series storage 4.3 Manual server configuration with iSCSI Use the Configure this host to access a Storage Center option in the Dell Storage Manager client to automatically configure a new iSCSI server object on the SC Series array, as shown in section 4.1. In cases where this is not possible, create the server object manually using the following steps. 1. Configure two physical NIC ports on the server to use iSCSI. 2.
Configure server objects on SC Series storage 8. From the Local adapter drop-down menu, select Microsoft iSCSI Initiator. From the Initiator IP drop-down menu, select the local IP address of the server NIC that is to be associated with iSCSI Fault Domain 1. The initiator IP in this example is 10.10.95.101. 9. Click OK, and then OK again to return to the iSCSI Initiator properties window. 10. Verify that the target IP address and adapter IP address are displayed in the Target portals section. 11.
Configure server objects on SC Series storage 15. On the Connect To Target screen, verify that both Add this connection to the list of Favorite Targets and Enable multi-path are checked. 16. Click Advanced to display additional options. 17. Set Local adapter to Microsoft iSCSI Initiator. 18. Select the correct IP addresses for the Target portal IP and Initiator IP from the drop-down menus. 19. Click OK, and click OK again to return to the iSCSI Initiator properties window. 20.
Configure server objects on SC Series storage 21. When finished, verify that all targets show with a status of Connected. 22. 23. 24. 25. 26. Click OK to exit the iSCSI Initiator Properties window. Log in to the desired SC Series array using the Dell Storage Manager client. Under Hardware, expand the Servers folder to the desired location. Right-click the desired folder and select Create Server. Under Host Bus Adapter, select the iSCSI ports for Fault Domains 1 and 2. 27.
Configure server objects on SC Series storage 4.4 Restrict volume mapping paths On an SC Series array that is configured to use both FC and iSCSI, it is possible to configure hosts to use FC, iSCSI, or both transports concurrently when mapping a SAN volume. While this is not a common configuration, there are valid use cases, such as when an environment migrates from one type of transport to another, and for a time, both transports are needed.
Configure MPIO 5 Configure MPIO This section describes how to associate the Microsoft DSM with SC Series volumes and how to set up and configure the Microsoft DSM based on the failover and load-balancing preferences of an organization. These instructions assume that server objects are created in Dell Storage Manager and that at least one volume is mapped to each server using FC, iSCSI, or SAS FE with MPIO enabled.
Configure MPIO 6. After rebooting, open the MPIO configuration tool and verify that COMPELNTCompellent Vol is listed under Devices under the MPIO Devices tab. 7. Click OK to close the window. 5.1.2 Using PowerShell (Windows Server 2012 or later) Windows Server 2012 or later includes the MPIO module in Windows PowerShell. Although the mpclaim command is included in Windows Server 2012 and above, Microsoft recommends using PowerShell.
Configure MPIO 3. Once the server reboots, use Disk Management to verify that the configuration is correct. There should only be one instance of each SAN volume listed in Disk Management. 5.2 Changing the default load balance policy Once SC Series volumes are associated with the Microsoft DSM on a Windows server, no further steps are necessary unless changing the Windows default MPIO load balance policy is necessary.
Configure MPIO 5.2.2 Using PowerShell (Windows Server 2012 or later) The MPIO module in PowerShell can be used to set the host server default load balance policy.
Configure MPIO 5. From the drop-down menu, select the appropriate MPIO policy for the volume. Make sure the chosen policy is supported or Windows will revert to the current default policy. 5.3.2 Using the MPCLAIM command To change the default load balance policy on a single volume, open a command prompt or PowerShell window with elevated (administrator) privileges (commands will work in both). Note: The load balance policy cannot be changed from round robin to failover only using the MPCLAIM command.
Configure MPIO Refer to Table 1 for a list of load balance policies and the associated numbers for the MPCLAIM command. To change the load balance policy of MPIO disk 2 from failover only to round robin, enter: mpclaim –l –d 2 2 To verify the new settings, enter: mpclaim –s –d Visit Microsoft TechNet for more information about using MPCLAIM.
Windows Server single-path and MPIO configuration recommendations for SC Series storage A Windows Server single-path and MPIO configuration recommendations for SC Series storage Observe the following guidelines before using this section. • • • • A.1 The recommended updates and hotfixes in this section list the names (msdsm.sys, mpio.sys, storport.sys, and msiscsi.sys) and modified dates of storage-specific files that are loaded when the associated update or hotfix is applied.
Windows Server single-path and MPIO configuration recommendations for SC Series storage A.2 Recommended updates and hotfixes for Windows Server 2012 (non-R2 version) See the Microsoft Update Catalog at https://www.catalog.update.microsoft.com/Home.aspx to locate specific KB downloads. Recommended updates and hotfixes for Windows Server 2012 (non-R2 version) KB number Title KB3018489 “No host bus adapter is present” error when http://support.microsoft.
Windows Server single-path and MPIO configuration recommendations for SC Series storage Note: Recommended registry settings apply to all versions of Windows Server unless directly specified. Recommended registry settings location: HKLM\SYSTEM\CurrentControlSet\Services\mpio\Parameters Default value Recommended value This setting controls the number of seconds that the multipath pseudo-LUN remains in system memory, even after losing all paths to the device.
Windows Server single-path and MPIO configuration recommendations for SC Series storage 29 Default value Setting name Description RetryInterval This setting specifies the interval of time 1 (in seconds) after which a failed request is retried (after the DSM has decided so, and assuming that the I/O has been retried a fewer number of times than RetryCount). This value is specified in seconds. The default is 1 second.
Windows Server single-path and MPIO configuration recommendations for SC Series storage Note: The registry settings in Table 5 need to be created on a Windows Server 2008 R2 server. Both settings should be created as DWORD (32-bit) values. Recommended disk registry settings location: HKLM\SYSTEM\CurrentControlSet\Services\mpio\Parameters Setting name Description Default Recommended value value DiskPathCheckEnabled If the DiskPathCheckEnabled key is set to a nonzero value, the MPIO component creates a pa
Windows Server single-path and MPIO configuration recommendations for SC Series storage A.5 iSCSI initiator settings (single-path and MPIO) This appendix contains recommended changes for iSCSI initiators. These changes apply to single-path and MPIO configurations that use iSCSI to connect to SC Series storage. Recommended iSCSI initiator registry settings location: HKLM\SYSTEM\CurrentControlSet\Control\Class\{4D36E97B-E325-11CE-BFC108002BE10318}\\Parameters 31 Default value Recommended
Windows Server single-path and MPIO configuration recommendations for SC Series storage Default value Recommended value This is the negotiated Max Burst Length. 262144 (256KB) no change This is the negotiated First Burst Length. 65536 (64KB) no change MaxRecvDataSegmentLength This is the negotiated MaxRecvDataSegmentLength. 65536 (64KB) no change IPSecConfigTimeout This timeout value is used when the driver calls the discovery service to configure\release IPsec for an iSCSI connection.
Windows Server single-path and MPIO configuration recommendations for SC Series storage Disable Nagle’s Algorithm: To disable delayed ACK and Nagle’s algorithm, create the following DWORD 32-bit entries for each SAN interface subkey in the Windows Server registry: HKLM\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\Interfaces\ • Create or verify these DWORD 32-bit entries. Set them to a value of 1 (disabled). TcpAckFrequency TcpNoDelay Disable NIC Interrupt Modulation: 1. 2. 3. 4.
Windows Server single-path and MPIO configuration recommendations for SC Series storage A.6 PowerShell script The following PowerShell script is provided as-is, with no warranty or guarantee of any kind implied, to set the recommended registry settings on Windows Server 2008 R2 or newer. The user assumes all risks for the use of, or results of using, this script. For hosts configured to use front-end SAS, the registry key RetryCount needs to be modified per Table 4.
Windows Server single-path and MPIO configuration recommendations for SC Series storage # iSCSI settings If ( ( Get-Service -Name "MSiSCSI" ).Status -eq "Running" ) { # Get the registry path for the Microsoft iSCSI initiator parameters $IscsiParam = Get-Item -Path $IscsiRegPath ` | Where-Object { ( Get-ItemProperty $_.PSPath ).DriverDesc ` -eq ` "Microsoft iSCSI Initiator" } ` | Get-ChildItem ` | Where-Object { $_.
Additional resources B Additional resources B.1 Technical support and resources Dell.com/support is focused on meeting customer needs with proven services and support. Dell TechCenter is an online technical community where IT professionals have access to numerous resources for Dell software, hardware, and services. Storage Solutions Technical Documents on Dell TechCenter provide expertise that helps to ensure customer success on Dell EMC storage platforms. B.
