HP serviceguard t2808-90006 manual Two Data Center and Quorum Service Location Architectures

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Building an Extended Distance Cluster Using Serviceguard and Software RAID

Two Data Center and Quorum Service Location Architectures

Two Data Center and Quorum Service Location Architectures

A two data center and Quorum Service location, which is at a third location, have the following configuration requirements:

There is no hard requirement on how far the Quorum Service location has to be from the two main data centers. It can be as close as the room next door with its own power source or can be as far as in another site across town. The distance between all three locations dictates that level of disaster tolerance a cluster can provide.

•In these solutions, there must be an equal number of nodes in each primary data center, and the third location (known as the arbitrator data center) contains the Quorum Server. LockLUN is not supported in a Disaster Tolerant configuration. In this release, only one node in each data center is supported.

•The Quorum Server is used as a tie-breaker to maintain cluster quorum when all communication between the two primary data centers is lost. The arbitrator data center must be located separately from the primary data centers. For more information about quorum server, see the Managing Serviceguard user’s guide and the Serviceguard Quorum Server Release Notes.

•A minimum of two heartbeat paths must be configured for all cluster nodes. The preferred solution is two separate heartbeat subnets configured in the cluster, each going over a separately routed network path to the other data center. Alternatively, there can be a single dedicated heartbeat subnet with a bonded pair configured for it. Each would go over a separately routed physical network path to the other data centers.

•There can be separate networking and Fibre Channel links between the data centers, or both networking and Fibre Channel can go over DWDM links between the data centers.

Chapter 2

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Contents Page Legal Notices Contents Disaster Scenarios and Their Handling Managing an MD Device Contents Contents Editions and Releases Printing HistoryHP Printing Division Document Organization Intended AudiencePage Related Page Disaster Tolerance Evaluating the Need for Disaster Tolerance Evaluating the Need for Disaster Tolerance High Availability Architecture What is a Disaster Tolerant Architecture?Node 1 fails Pkg B Client ConnectionsDisaster Tolerant Architecture Extended Distance Clusters Understanding Types of Disaster Tolerant ClustersFrom both storage devices Extended Distance Cluster Two Data Center Setup Benefits of Extended Distance Cluster Cluster Extension CLX Cluster CLX for Linux Serviceguard Cluster Shows a CLX for a Linux Serviceguard cluster architectureBenefits of CLX Differences Between Extended Distance Cluster and CLX Continental Cluster New York Cluster Los Angeles ClusterData Cent er a Data Center B Continental ClusterBenefits of Continentalclusters Continental Cluster With Cascading Failover Comparison of Disaster Tolerant SolutionsAttributes Extended Distance Comparison of Disaster Tolerant Cluster SolutionsContinentalclusters Cluster HP-UX onlyUnderstanding Types of Disaster Tolerant Clusters Understanding Types of Disaster Tolerant Clusters Understanding Types of Disaster Tolerant Clusters WAN EVA Protecting Nodes through Geographic Dispersion Disaster Tolerant Architecture GuidelinesOff-line Data Replication Protecting Data through ReplicationPhysical Data Replication On-line Data ReplicationDisadvantages of physical replication in hardware are Advantages of physical replication in hardware areAdvantages of physical replication in software are Logical Data Replication Disadvantages of physical replication in software areDisadvantages of logical replication are Ideal Data Replication Using Alternative Power SourcesPower Circuit 1 node Alternative Power SourcesData Center a Node 3 Power Circuit Creating Highly Available NetworkingDisaster Tolerant Wide Area Networking Disaster Tolerant Local Area NetworkingDisaster Tolerant Cluster Limitations Managing a Disaster Tolerant Environment Manage it in-house, or hire a service?How is the cluster maintained? Additional Disaster Tolerant Solutions Information Building an Extended Distance Dwdm Types of Data Link for Storage NetworkingTwo Data Center and Quorum Service Location Architectures Two Data Center and Quorum Service Location Architectures Server Two Data Centers and Third Location with Dwdm and QuorumTwo 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 Installing XDC Installing the Extended Distance Cluster SoftwareSupported Operating Systems Prerequisites# rpm -Uvh xdc-A.01.00-0.rhel4.noarch.rpm Verifying the XDC InstallationInstalling the Extended Distance Cluster Software Configuring the Environment Configuring the Environment Configuring the Environment Setting the Value of the Link Down Timeout Parameter Configuring Multiple Paths to StorageCluster Reformation Time and Timeout Values Http//docs.hp.com Using Persistent Device NamesTo Create and Assemble an MD Device Creating a Multiple Disk 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 Cat /proc/mdstat Viewing the Status of the MD DeviceExample A-1 Stopping the MD Device /dev/md0 Stopping the MD DeviceExample A-2 Starting the MD Device /dev/md0 Starting the MD Device# udevinfo -q symlink -n sdc1 Removing and Adding an MD Mirror Component Disk# mdadm --remove /dev/md0 /dev/hpdev/sde Adding a Mirror Component DeviceIndex 104