Best Practices Dell EMC SC Series: Microsoft Multipath I/O Best Practices Abstract This document provides best practices for configuring Microsoft® Multipath I/O (MPIO) to perform optimally 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 6.3 iSCSI .................................................................................................................................................................21 6.3.1 Assign IP addresses and enable Jumbo Frames .............................................................................................22 7 Configure server object on SC Series ........................................................................................................................23 7.
Table of contents A.5 B 5 iSCSI initiator settings (single-path and MPIO) ................................................................................................55 Additional resources ...................................................................................................................................................58 B.1 Technical support and resources .....................................................................................................................58 B.
Executive summary Executive summary This document provides best practices for deploying Microsoft® Windows Server® Multipath IO (MPIO) with Dell EMC™ SC Series storage. For your specific SC Series array and Storage Center OS (SCOS) version, refer to the primary reference material at Dell.com/support for optimal configuration of SC Series storage for Windows Server.
Introduction to Microsoft MPIO 1 Introduction to Microsoft MPIO Microsoft MPIO is a framework that allows administrators to configure load balancing and failover processes using multiple data paths to external storage. Supported transports include Fibre Channel (FC) and iSCSI in a storage area network (SAN) configuration, and serial-attached SCSI (SAS) front-end connections in a directattach storage (DAS) configuration.
Introduction to Microsoft MPIO Microsoft provides a built-in DSM for Windows Server 2008 R2 and above that is fully compatible with SC Series storage and is the focus of this paper. The built-in DSM is available after installing the Multipath IO feature. The MPIO feature is not installed on a Windows Server by default. Install the Windows Server Multipath I/O feature to support MPIO with SC Series storage 1.
Introduction to Microsoft MPIO • • • • • • • • • • 9 Install a supported MPIO card in the host server Verify that current firmware is applied to all hardware (servers, MPIO cards, switches) Verify current OS drivers for the MPIO card Configure the MPIO card (HBA) firmware settings Configure cabling and the storage area network Create server object on the SC Series array Present an SC Series volume as a LUN to the host server Apply the Microsoft DSM and configure MPIO settings on the host server Adjust Win
MPIO design, scale, and performance considerations 2 MPIO design, scale, and performance considerations Plan for scale and performance. If the environment is new, ensure that the design will support the workload. See the Dell EMC SC Series Storage and Microsoft Windows Server best practice guide for information on right-sizing the SC Series storage array and storage fabric to maximize throughput and minimize latency. 2.
MPIO design, scale, and performance considerations 2.3 Virtual port mode 1 8 4 2 8 4 2 PORT 1 PCIe x8 8Gb FC Server PORT 2 Virtual port mode is the recommended configuration for Microsoft environments. In virtual port mode, all frontend I/O ports that are assigned to fault domains are configured as active ports. Because all ports are active, additional front-end bandwidth is available without sacrificing redundancy.
MPIO design, scale, and performance considerations Note: In virtual port mode, SC Series storage presents iSCSI control ports to host servers. Servers connect to control ports and the SC Series array redirects traffic automatically to the appropriate virtual port. 2.4 SAS front-end support SAS front-end (SAS FE) is a simple, cost-effective transport option that is ideal for edge cases such as a small branch office or remote location with a few host servers.
Patch Windows Server OS and install MPIO 3 Patch Windows Server OS and install MPIO Prepare the host server for MPIO by following the steps in this section. 3.1 Apply OS patches and updates Leverage Microsoft Updates to fully patch the Windows Server OS. Verify that Microsoft Updates do not downgrade the Windows Server drivers for any MPIO cards already installed in the host server. 3.2 Install MPIO Install the Multipath I/O feature on the Windows Server host and reboot.
Patch Windows Server OS and install MPIO Enable support for iSCSI or SAS devices after installing the MPIO feature After enabling support for iSCSI or SAS devices, reboot the Windows Server host.
Install and update an MPIO card 4 Install and update an MPIO card Follow the steps in this section to install and update a supported MPIO card in the Windows Server OS. 4.1 Verify the hardware is supported Ensure that all hardware components in the storage data path are supported. This includes all FC, iSCSI, SAS cards, and FC/iSCSI switches. See the Dell EMC Storage Compatibly Matrix for a list of supported hardware. QLogic 32Gb FC PCIe card with two host server ports (HBAs) 4.
Install and update an MPIO card 4.3.1 Firmware For Dell EMC PowerEdge™ servers, leverage the LifeCycle Controller (LC) or other options such as the latest Platform Specific Bootable ISO (PSBI) image to update server components. This will update the firmware for installed FC, iSCSI, and SAS cards that have Dell EMC drivers.
Configure MPIO card firmware 5 Configure MPIO card firmware Configure the firmware settings for the MPIO card, if required. Each card will typically contain one to four host ports (HBAs) each. The examples shown in this document show cards with two HBAs each. 5.1 SAS-FE Supported SAS FE cards work out-of-the-box with the default firmware settings. No additional configuration is required. 5.2 FC FC cards may require firmware configuration to enable each port and to set parameters.
Configure MPIO card firmware 4. Reset the host adapter to factory defaults by selecting Configuration Settings > Restore Default Settings. 5. Return to the main screen and select any additional HBAs one at a time and reset them to factory defaults. 6. Reboot the host server and press Ctrl+Q when prompted to access Fast!UTIL. 7. Set the following parameters on the first HBA: a. Under Configuration Settings > Adapter Settings: i. Set Host Adapter BIOS to Enabled. ii.
Configure MPIO card firmware b. Under Configuration Settings > Advanced Adapter Settings: i. Set Luns per Target to 256. ii. Set Enable LIP Reset to Yes. iii. Set Enable LIP Full Login to Yes. iv. Set Login Retry Count to 60. v. Set Port Down Retry Count to 60. vi. Set Link Down Timeout to 30. vii. Leave all other settings at the defaults. viii. Press Esc twice and save the changes when prompted. 8. Repeat for each additional HBA listed on the main screen in Fast!UTIL. 9.
Install cabling and configure the storage network 6 Install cabling and configure the storage network Verify that cabling is connected between the host server MPIO card (the HBAs or NIC ports), switches, and the SC Series array, and then configure the storage network. 6.1 SAS-FE For SAS-FE, switches are not used. Connect SAS cables from the SAS ports on the host server directly to SAS-FE ports on the SC Series array.
Install cabling and configure the storage network fabric. This guide assumes two separate virtual-port FC fault domains and fabrics are configured for redundancy (see Figure 4). 6.3 iSCSI For iSCSI, verify that patch cables (typically RJ45 Cat5e/Cat6 or SFP-based) are connected from the NIC ports in the host server to switch ports, and from switch ports to the iSCSI ports on the SC Series array. SC Series storage does not support connecting iSCSI cables from a host directly to the array.
Install cabling and configure the storage network VLANs on a shared switch isolate iSCSI traffic and iSCSI fault domains If a converged network adapter (CNA) is used on the host that combines iSCSI and other IP traffic over the same cable, configure VLANs to isolate the iSCSI traffic. 6.3.1 Assign IP addresses and enable Jumbo Frames Once cabling is in place, assign IPs to each iSCSI port on the host and verify that the host can see the target iSCSI port IPs on the SC Series array.
Configure server object on SC Series 7 Configure server object on SC Series A server object representing the Windows Server host and MPIO ports (SAS, FC, or iSCSI) or can now be created on the SC Series array. Server objects organized under subfolders on the SC Series array There are two ways to create a new server object on SC Series: automatic or manual. The automatic method is recommended where supported. The manual method is required when a host is configured to boot-from-SAN with FC or iSCSI.
Configure server object on SC Series Follow these steps for automatic creation: 1. Install the latest Dell Storage Manager client version on the Windows Server host. 2. Right-click the Dell Storage Manager client icon and select Run as administrator to launch the client with administrator rights. 3. On the Dell Storage Manager client launch screen, select the Configure this host to access a Storage Center option. 4. Provide access information for the desired SC Series array. 5.
Configure server object on SC Series 6. Verify that the expected Windows Server host MPIO ports are listed. The two examples below show discovery from a Windows Server host named S1352 with a dual-HBA FC card, and a Windows Server host named S1353 with a dual-port NIC that supports iSCSI. In both examples, there are two separate fault domains on the SC Series array. Click Next. 7. Allow the wizard to complete.
Configure server object on SC Series 8. The wizard will display a list changes made to the Windows Server. These changes optimize the Windows Server for MPIO performance and resiliency. Note: Additional registry changes may be required for your transport and OS version, as listed in appendix A. Use PowerShell or regedit to make additional adjustments as needed. 9. Optional: Check Launch wizard to create a volume for this host to create and add an SC Series volume to this host.
Configure server object on SC Series 7.2.1 SAS-FE manual configuration To create a server object manually when a host has SAS HBAs, refer to the Dell EMC SC Series Storage with SAS Front-end for Microsoft configuration guide. 7.2.2 FC manual configuration To create a server object manually when a host has FC HBAs, follow these steps: 1.
Configure server object on SC Series 9. If the Windows Server host HBAs are not listed but should be, troubleshoot the issue. Once resolved, repeat the steps in this section. Note: Although HBAs can added by manually typing in the WWN (if the server or HBA is off line for example), this is not advised. Mapping HBAs that are visible is highly recommended as a best practice because it helps to confirm correct configuration of the Windows Server host, HBAs, and the storage network. 10.
Configure server object on SC Series 5. Enter the target IP address for the control port for first iSCSI Fault Domain on the SC Series array. In this example, the target IP is 10.10.17.10. Click Advanced. 6. Set Local adapter to Microsoft iSCSI Initiator, and Initiator IP to the local IP address of the server NIC that is on the same subnet or VLAN as the target IP in step 5. The iSCSI initiator (host) IP in this example is 10.10.134.53. 7. Click OK twice to return to the iSCSI Initiator properties window.
Configure server object on SC Series 10. When completed, verify that both sets of iSCSI target IPs (left) and initiator IPs (right) are listed. 11. Select the Targets tab. This should be populated with the discovered iSCSI target ports on the SC array, with a status of Inactive. 12. Click the first target to select it and click Connect.
Configure server object on SC Series 13. Check the box to Enable multi-path. The option Add this connection… should already be selected. 14. Click Advanced. 15. Using the drop-down lists, do the following: a. Set Local adapter to Microsoft iSCSI Initiator. b. Select the Target portal IP address. c. Select the matching Initiator IP (host server iSCSI IP) address. Make sure the target and initiator IPs are in the same network or VLAN. d. Click OK twice to return to the iSCSI Initiator properties window. 16.
Configure server object on SC Series 17. When finished, verify that all targets show with a status of Connected. Each target name includes a virtual WWN that corresponds with a matching virtual iSCSI port on the SC Series array. Virtual WWNs 18. 19. 20. 21. 32 Click OK to exit the iSCSI Initiator Properties window. Log in to the desired SC Series array using the Dell Storage Manager client. Under the Storage tab, expand the Servers folder to the desired location.
Configure server object on SC Series 22. Under Host Bus Adapter, select the iSCSI control port for the host server. If the expected port is not listed, refresh the Dell Storage Manager client. With older versions of SCOS, the wizard may display two iSCSI HBAs for the host server. If so, select both. 23. Once created, verify that the server object lists the iSCSI HBA and the controller ports under each fault domain under the Connectivity tab with a status of Up. 24.
Present SC Series storage and apply the Microsoft DSM 8 Present SC Series storage and apply the Microsoft DSM Verify that all the steps in the previous sections of this guide have been completed before attempting to present SC Series storage to a Windows Server host that is configured for MPIO. 1. Use the Dell Storage Manager client to create a new volume on the SC Series array. 2. Map this SC Series volume to the Windows Server host as a new SAS-FE, FC, or iSCSI LUN.
Present SC Series storage and apply the Microsoft DSM 4. The MPIO tab will show the default MPIO policy for the transport, the DSM as Microsoft DSM, and two or more paths. If the server is configured to use single path, the MPIO tab is not present. 5. Configure MPIO timeout settings. Note: The MPIO timeout settings and hotfixes are required with SC Series storage even if the server is configured to use single-path. a.
Present SC Series storage and apply the Microsoft DSM 8.2 Duplicate volume instances are listed in Disk Management This section describes how to resolve duplicate volume instances by applying the Microsoft DSM to SC Series volumes to support MPIO. This is required when multiple instances of the same disk are listed in Disk Management.
Present SC Series storage and apply the Microsoft DSM 3. For a FC configuration, click COMPELNTCompellent Vol and click Add. 4. Reboot the server when prompted (required). 8.2.2 Apply the MS-DSM with PowerShell (Windows Server 2012 and 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.
Present SC Series storage and apply the Microsoft DSM 3. Once the server reboots, use Disk Management to verify that the configuration is correct. There should only be one instance of the SAN volume listed in Disk Management. 8.2.4 Verify single instance of the disk To verify that there is now a single instance of the SC volume, complete these steps: 1. 2. 3. 4. 5. 6. Log in to Windows and launch Disk Management. Only one instance of the disk should now be listed.
Multiple transports and volume mapping 9 Multiple transports and volume mapping On an SC Series array that is configured to use multiple front-end transports concurrently, mapping volumes to host servers using multiple transports is supported, however, there is limited Windows Server support. For example, if the SC Series array and a host server both support FC and iSCSI, when mapping a new volume to the host, all available FC and iSCSI paths will be mapped by default. 9.
Change the default load balance policy 10 Change 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. The best practice recommendation is to allow Windows Server to detect and use the appropriate load balance policy for SC Series volumes. Changing the default policy to an optional policy is discouraged.
Change the default load balance policy Parameter Definition 4 Least queue depth 5 Weighted paths 6 Least blocks 7 Vendor specific For example, to change all SC Series volumes to a failover only policy, enter the following command: mpclaim.exe -L -M 1 -d "COMPELNTCompellent Vol" 10.2 PowerShell (Windows Server 2012 or later) Use the MPIO module in PowerShell to change the host server default load balance policy. Open a PowerShell window with elevated (administrator) privilege.
Change the default load balance policy 5. From the drop-down menu, select the desired MPIO policy for the volume. Note: If a host server defaults to round robin for a volume use case, attempting to select round robin with subset will result in the policy reverting to back to round robin. The reverse is also true if a host server defaults to round robin with subset for a volume use case. Attempting to select round robin will result in the policy reverting back to round robin with subset. 10.3.
Change the default load balance policy The syntax to change the load balance policy on a specific volume is as follows: mpclaim –l –d <0-7> 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 the Microsoft Documentation Library for more information about using MPCLAIM.
Boot-from-SAN 11 Boot-from-SAN SC Series storage supports boot-from-SAN when hosts are equipped with a supported FC or iSCSI MPIO card that supports a boot-from-SAN configuration. Note: Booting from a DAS volume with SAS-FE is not supported with SC Series. 11.1 Boot-from-SAN advantages • • • 11.2 Boot from local disk advantages • • 11.3 Use SC Series snapshots of boot volumes for quick recovery.
Boot-from-SAN 11.3.1 FC boot-from-SAN The example below will show how to configure a QLogic FC card to support boot from SAN. See the manufacturer documentation for how to configure boot-from-SAN for other supported FC or iSCSI MPIO cards. 1. Boot the server and press Ctrl+Q when prompted to access the Fast!UTIL utility. 2. Verify correct firmware settings for each HBA (see section 5). 3. Verify that all fabric and zoning steps have been completed (see section 6). 4.
Boot-from-SAN 6. Once the boot volume is mapped as LUN 0, view the Mappings tab to verify the presence of all expected HBAs (two in this example) with a status of Up. 7. Using Fast!UTIL, go to Selectable Boot Settings for the first HBA and set Selectable Boot to Enabled. 8. Arrow down to the first boot port and press Enter. One or more boot ports should be listed, depending on how many front-end ports are configured on your SC Series array.
Boot-from-SAN 10. If there is more than one boot port available, repeat this step until all boot ports for this adapter are added. In this example, there is one boot port for each HBA. 11. Save the changes. 12. On the Fast!UTIL main menu, select the next HBA port, repeat the above steps to add the boot ports, and save the changes. In this example, the FC card has two HBAs, each with a boot port defined. 13.
Boot-from-SAN figure below shows the system setup of a Dell EMC PowerEdge server where a QLogic FC HBA is configured as the first boot device. 16. Stage an OS to LUN 0 following your preferred staging method. For PowerEdge servers, it is a best practice to leverage the LifeCycle controller to broker the OS install as this method will use the latest OS driver pack from Dell EMC. 17. Once the OS is installed and fully patched, install the Windows Server MPIO feature and reboot.
Boot-from-SAN 18. On the SC Series array, change the Server Properties for the host from single path back to MPIO. 19. Launch the MPIO feature on the host, and under Discover Multi-Paths, select and install the COMPELNTCompellent Vol item and reboot the host. It may be necessary to first perform a manual disk rescan using Disk Management, or a reboot of the host. 20. After rebooting, verify that this MPIO device is listed under the MPIO Devices tab on the host.
Boot-from-SAN 21. Verify that only one instance of the boot volume is listed in Disk Management, and that all expected paths are present. Where the default policy is round robin (typical), all paths will show as Active/Optimized. 22. Go to appendix A and adjust the MPIO timeout settings and apply hotfixes as applicable (even if the server is using single-path). 11.3.2 iSCSI boot-from-SAN Consult the manufacturer documentation for your iSCSI card to configure boot-from-SAN.
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 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.com/kb/3018489 querying SAS cable issues in Windows Server 2012 R2 or Windows Server 2012 storport.
Windows Server single-path and MPIO configuration recommendations for SC Series storage 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 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 Recommended disk registry settings location: HKLM\SYSTEM\CurrentControlSet\Services\disk Setting name Description TimeoutValue Disk time-out is a registry setting that defines the time that Windows will wait for a hard disk to respond to a command. Installing host bus adapters (HBA) or other storage controllers can cause this key to be created and configured. A.
Windows Server single-path and MPIO configuration recommendations for SC Series storage 56 Default value Recommended value Setting name Description MaxPendingRequests This setting controls the maximum number 255 of outstanding requests allowed by the initiator. At most this many requests will be sent to the target before receiving response for any of the requests. no change EnableNOPOut If set to 1, the initiator will send NOP OUT PDUs to target if there is no activity for 2 minutes.
Windows Server single-path and MPIO configuration recommendations for SC Series storage Note the following additional guidelines: Enable RFC1323 timestamps (TCP High Performance Extensions) to prevent sequence number wrap under high load, known as Prevention Against Wrapped Sequence (PAWS). High-load iSCSI connections are prone to this issue, particularly at 10GbE or higher.
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. Storage technical documents and videos provides expertise that helps to ensure customer success on Dell EMC storage platforms. B.
