Dell Computer Drive manual Data Path Protection, Failover with Red Hat Enterprise Linux

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I/O Data Path Protection

You can have multiple host-to-array connections for a host. Make sure to select all of the connections to the array when configuring host access to the storage array.

NOTICE: Refer to the Installation Guide for more information on cabling configurations.

NOTE: For maximum redundancy, you must select all host connections to the array when manually defining host topology. For example, a host might have two host connections. For this host, you would select two host connections.

If a component such as a RAID controller module or a cable fails, or an error occurs on the data path to the preferred RAID controller module, virtual disk ownership is moved to the alternate nonpreferred RAID controller module for processing. This failure or error is called failover.

Multi-path drivers such as MPIO and MPP are installed on host systems that access the storage array and provide I/O path failover. The multi-path driver (MPIO in Windows and MPP in Linux) is used for failover. Automatic Virtual Disk Transfer (AVT) is used specifically for single-port cluster failover. The AVT feature mode is automatically selected by host type.

NOTE: You should have the multi-path driver installed on the hosts at all times, even in a configuration where there is only one path to the storage system, such as a single port cluster configuration.

During a failover, the virtual disk transfer is logged as a critical event, and an alert notification is sent automatically if you have configured alert destinations for the storage array.

Failover with Red Hat Enterprise Linux

For users running Red Hat Enterprise Linux Version 3.0 (x86), the mpp_vhba failover driver component does not load unless a storage array is connected and a LUN is mapped to the host server. Follow these steps to ensure proper MPP driver loading and LUN mapping:

1Ensure that the storage array is connected to the host server and that out- of-band (Ethernet) connections to each RAID controller module exist.

2Create a virtual disk and map it to LUN 0.

3Reboot the host.

About Your Host

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Contents W . d e l l . c o m s u p p o r t . d e l l . c o m Dell PowerVault Modular Disk Storage Manager User’s GuideFebruary Contents Connecting the Serial Cable System Setup for Password Reset Viewing iSCSI Statistics and Setting Baseline Disk Groups and Virtual Disks Premium Feature-Snapshot Virtual Disks Troubleshooting Problems 101 Contents User Interface About This GuideConfigure Tab Summary TabModify Tab Tools Tab ISCSI TabSupport Tab View online help View the event log Other Information You May NeedAbout Your Storage Array Access Virtual DiskOut-of-Band and In-Band Management Adding Storage Arrays Automatic Discovery of Storage ArraysManual Addition of a Storage Array Removing Storage Arrays Naming Storage ArraysInitial setup tasks include Setting Up Your Storage ArrayStorage Array Setting a Password To set, change, or remove a password for a storage arrayStorage Array Support Data Consider these guidelines when you create a password Resetting a PasswordPassword Guidelines Connecting the Serial CableMicrosoft Windows Operating Systems System Setup for Password ResetReset Password Configuring Alert Notifications Configuring E-mail AlertsChanging Expansion Enclosure ID Numbers Storage Array Configuring Snmp Alerts Starting or Restarting the Host-Agent Software in Linux Starting or Restarting the Host-Agent Software in WindowsStorage Array Storage Array Using the iSCSI Tab Using iSCSIChanging the iSCSI Target Authentication Entering Mutual Authentication PermissionsCreating Chap Secrets Valid Ascii Characters for Chap Secrets Space Using iSCSI Changing the iSCSI Target Identification Changing the iSCSI Target DiscoveryType the alias in the iSCSI target alias field and click OK Advanced iSCSI Host Ports Settings Configuring the MD3000i iSCSI Host PortsViewing or Ending an iSCSI Session Lowest priority defaultViewing iSCSI Statistics and Setting Baseline Statistics Edit, Remove, or Rename Host Topology Host Topology Actions Desired Action Using iSCSI Service Status area, click Start Linux Event MonitorEnabling the Event Monitor Disabling the Event Monitor About Your Host Configuring Host AccessManual Configuration using SAS HBA Automatic ConfigurationClick Next Manual Configuration using iSCSIRemoving Host Access Host Groups Creating a Host GroupAdding a Host to a Host Group Moving a Host to a Different Host Group Removing a Host From a Host GroupRemoving a Host Group Host TopologyHost Context Agent Create a virtual disk and map it to LUN Reboot the host Data Path ProtectionFailover with Red Hat Enterprise Linux About Your Host Disk Groups and Virtual Disks Creating Disk Groups and Virtual Disks Manual Configuration Disk Groups and Virtual Disks Disk Groups and Virtual Disks Hot Spare Drive Protection Automatically Configuring Hot SparesClick OK in the dialog box Manually Configuring Hot SparesHost-to-Virtual Disk Mapping Creating Host-to-Virtual Disk MappingsModifying and Removing Host-to-Virtual Disk Mapping Changing Controller Ownership of the Virtual Disk Storage PartitioningDisk Group and Virtual Disk Expansion Disk Group ExpansionVirtual Disk Expansion Changing Media Scan Settings Errors discovered by the media scan includeStorage Array Media Scan Microsoft Services Virtual Disk ServiceSuspending the Media Scan Volume Shadow-Copy Service Disk Groups and Virtual Disks Premium Feature-Snapshot Virtual Disks About the Simple Path Creating a Snapshot Virtual Disk Using the Simple PathHost-to-Virtual Disk Mapping The default setting is Map now SMrepassist -ffilename-identifier Creating the Snapshot Using the Simple Path Snapshot Virtual Disks About the Advanced Path Creating a Snapshot Virtual Disk Using the Advanced PathSnapshot Virtual Disks SMrepassist -ffilename-identifier Creating the Snapshot Using the Advanced Path Snapshot Virtual Disks Source-virtual disk-name-sequence-number Specifying Snapshot Virtual Disk NamesSnapshot Repository Capacity Disabling a Snapshot Virtual Disk Re-creating Snapshot Virtual DisksPreparing Host Servers to Re-create a Snapshot Virtual Disk To disable a snapshot virtual diskRe-creating a Snapshot Virtual Disk Premium Feature-Virtual Disk Copy Reasons to use virtual disk copy include the following Creating a Virtual Disk Copy for an Mscs Shared DiskVirtual Disk Read/Write Permissions If you are using the target virtual disk for backup purposesVirtual Disk Copy Restrictions Preparing Host Servers to Create a Virtual Disk Copy Creating a Virtual Disk CopyCopying the Virtual Disk Choose the target virtual diskClick Next at the bottom Storage Array Performance During Virtual Disk Copy Setting Copy PriorityClick Yes to stop the virtual disk copy Stopping a Virtual Disk CopyRecopying a Virtual Disk To stop a virtual disk copy, complete the following stepsPreparing Host Servers to Recopy a Virtual Disk Recopying the Virtual Disk Removing Copy Pairs Virtual Disk Copy Downloading RAID Controller and Nvsram Packages Firmware DownloadsDownloading Both RAID Controller and Nvsram Firmware Downloading Non-redundant Mscs Nvsram Firmware Downloading Only Nvsram FirmwareDownloading Physical Disk Firmware Downloading EMM Firmware 100 Device Health Conditions Troubleshooting ProblemsRecovery Guru Storage Array Profile102 SMrepassist UtilitySupport Information Package Click Browse103 Unidentified Devices Recovering from an Unidentified Storage Array105 Ping host-name-or-IP-address-of-the-hostTroubleshooting Removing an EMM from the Expansion Enclosure Inserting an EMM into an Expansion Enclosure107 MD3000 Maintenance Considerations Removing and Inserting Physical Disks108 109 110 111 IndexIndex 113 114