HP serviceguard t2808-90006 manual Chapter

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Configuring your Environment for Software RAID

Creating Volume Groups and Configuring VG Exclusive Activation on the MD Mirror

NOTE

Creating Volume Groups and Configuring VG Exclusive Activation on the MD Mirror

Once you create the MD mirror device, you need to create volume groups and logical volumes on it.

XDC A.01.00 does not support configuring multiple raid1 devices as physical volumes in a single volume group.

For example, if you create a volume group vg01, it can have only one MD raid1 device /dev/md0 as its physical volume.

To configure multiple raid1 devices as physical volumes in a single volume group, you must install the XDC A.01.02 patch. To install this patch, you must first upgrade to HP Serviceguard A.11.18 and the latest version of XDC. After upgrading, install the A.01.02 patch that is specific to the operating system in your environment.

XDC A.01.02 contains the following patches for Red Hat and SuSE Linux operating systems:

•SGLX_00133 for Red Hat Enterprise Linux 4

•SGLX_00134 for Red Hat Enterprise Linux 5

•SGLX_00135 for SUSE Linux Enterprise Server 10

You can contact the HP support personnel to obtain these patches.

When you create a logical volume on an MD device, the actual physical devices that form the MD raid1 mirror must be filtered out to avoid receiving messages from LVM about duplicate PV entries.

For example, let us assume that /dev/sde and /dev/sdf are two physical disks that form the md device /dev/md0. The persistent device names for /dev/sde and /dev/sdf are /dev/hpdev/md0_mirror0 and /dev/hpdev/md0_mirror1 respectively. When you create a logical volume, duplicate entries are detected for the two physical disks that form the mirror device. As a result, the logical volume is not created and an error message is displayed. Following is a sample of the error message that is displayed:

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Chapter 3

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Contents Page Legal Notices Contents Disaster Scenarios and Their Handling Managing an MD Device Contents Contents Printing History Editions and ReleasesHP Printing Division Intended Audience Document OrganizationPage Related Page Disaster Tolerance Evaluating the Need for Disaster Tolerance Evaluating the Need for Disaster Tolerance Node 1 fails What is a Disaster Tolerant Architecture?High Availability Architecture Pkg B Client ConnectionsDisaster Tolerant Architecture Understanding Types of Disaster Tolerant Clusters Extended Distance ClustersFrom both storage devices Extended Distance Cluster Two Data Center Setup Benefits of Extended Distance Cluster Cluster Extension CLX Cluster Shows a CLX for a Linux Serviceguard cluster architecture CLX for Linux Serviceguard ClusterBenefits of CLX Differences Between Extended Distance Cluster and CLX Continental Cluster Data Cent er a Data Center B Los Angeles ClusterNew York Cluster Continental ClusterBenefits of Continentalclusters Comparison of Disaster Tolerant Solutions Continental Cluster With Cascading FailoverContinentalclusters Comparison of Disaster Tolerant Cluster SolutionsAttributes Extended Distance Cluster HP-UX onlyUnderstanding Types of Disaster Tolerant Clusters Understanding Types of Disaster Tolerant Clusters Understanding Types of Disaster Tolerant Clusters WAN EVA Disaster Tolerant Architecture Guidelines Protecting Nodes through Geographic DispersionProtecting Data through Replication Off-line Data ReplicationOn-line Data Replication Physical Data ReplicationAdvantages of physical replication in hardware are Disadvantages of physical replication in hardware areAdvantages of physical replication in software are Disadvantages of physical replication in software are Logical Data ReplicationDisadvantages of logical replication are Using Alternative Power Sources Ideal Data ReplicationData Center a Node 3 Power Circuit Alternative Power SourcesPower Circuit 1 node Creating Highly Available NetworkingDisaster Tolerant Local Area Networking Disaster Tolerant Wide Area NetworkingDisaster Tolerant Cluster Limitations Manage it in-house, or hire a service? Managing a Disaster Tolerant EnvironmentHow is the cluster maintained? Additional Disaster Tolerant Solutions Information Building an Extended Distance Types of Data Link for Storage Networking DwdmTwo Data Center and Quorum Service Location Architectures Two Data Center and Quorum Service Location Architectures Two Data Centers and Third Location with Dwdm and Quorum ServerTwo Data Center and Quorum Service Location Architectures Rules for Separate Network and Data Links Guidelines on Dwdm Links for Network and Data Guidelines on Dwdm Links for Network and Data Guidelines on Dwdm Links for Network and Data Chapter Configuring your Environment Understanding Software RAID Supported Operating Systems Installing the Extended Distance Cluster SoftwareInstalling XDC PrerequisitesVerifying the XDC Installation # rpm -Uvh xdc-A.01.00-0.rhel4.noarch.rpmInstalling the Extended Distance Cluster Software Configuring the Environment Configuring the Environment Configuring the Environment Configuring Multiple Paths to Storage Setting the Value of the Link Down Timeout ParameterCluster Reformation Time and Timeout Values Using Persistent Device Names Http//docs.hp.comCreating a Multiple Disk Device To Create and Assemble an MD Device# mdadm -A -R /dev/md0 /dev/hpdev/sde1 /dev/hpdev/sdf1 Chapter Linux #RAIDTAB= # MD RAID Commands To Edit the Datarep Variable Creating and Editing the Package Control ScriptsTo Create a Package Control Script Editing the raid.conf File To Edit the Xdcconfig File parameterTo Configure the RAID Monitoring Service Cases to Consider when Setting Rpotarget RPO Target Definitions Chapter Multipledevices and Componentdevices Raidmonitorinterval Configuring your Environment for Software RAID Disaster Scenario What happens when this disaster occursRecovery Process Disaster Scenarios and Their Handling Disaster Scenarios and Their Handling# mdadm --remove /dev/md0 # mdadm -add /dev/md0 Dev/hpdev/mylink-sdf P1 uses a mirror md0 Run the following command to S2 is non-current by less # cmrunpkg packagename Execute the commands that With md0 consisting of only N1, for example Becomes accessible from N2 Center Disaster Scenarios and Their Handling Managing an MD Device Viewing the Status of the MD Device Cat /proc/mdstatStopping the MD Device Example A-1 Stopping the MD Device /dev/md0Starting the MD Device Example A-2 Starting the MD Device /dev/md0Removing and Adding an MD Mirror Component Disk # udevinfo -q symlink -n sdc1Adding a Mirror Component Device # mdadm --remove /dev/md0 /dev/hpdev/sdeIndex 104