HP serviceguard t2808-90006 manual Disaster Tolerant Local Area Networking

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Disaster Tolerance and Recovery in a Serviceguard Cluster

Disaster Tolerant Architecture Guidelines

Disaster Tolerant Local Area Networking

Ethernet networks can also be used to connect nodes in a disaster tolerant architecture within the following guidelines:

•Each node is connected to redundant switches and bridges using two Ethernet host adapters. Bridges, repeaters, or other components that convert from copper to fibre cable may be used to span longer distances.

Disaster Tolerant Wide Area Networking

Disaster tolerant networking for continental clusters is directly tied to the data replication method. In addition to the redundant lines connecting the remote nodes, you also need to consider what bandwidth you need to support the data replication method you have chosen. A continental cluster that handles a high number of transactions per minute will not only require a highly available network, but also one with a large amount of bandwidth.

This is a brief discussion of things to consider when choosing the network configuration for your continental cluster. Details on WAN choices and configurations can be found in Continental Cluster documentation available from: http://docs.hp.com -> High Availability.

•Bandwidth affects the rate of data replication, and therefore the currency of the data should there be the need to switch control to another site. The greater the number of transactions you process, the more bandwidth you will need. The following connection types offer differing amounts of bandwidth:

—T1 and T3: low end

—ISDN and DSL: medium bandwidth

—ATM: high end

•Reliability affects whether or not data replication happens, and therefore the consistency of the data should you need to fail over to the recovery cluster. Redundant leased lines should be used, and should be from two different common carriers, if possible.

•Cost influences both bandwidth and reliability. Higher bandwidth and dual leased lines cost more. It is best to address data consistency issues first by installing redundant lines, then weigh the price of data currency and select the line speed accordingly.

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Chapter 1

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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 Create a Package Control Script Creating and Editing the Package Control ScriptsTo Edit the Datarep Variable To Configure the RAID Monitoring Service To Edit the Xdcconfig File parameterEditing the raid.conf File Cases to Consider when Setting Rpotarget RPO Target Definitions Chapter Multipledevices and Componentdevices Raidmonitorinterval Configuring your Environment for Software RAID Recovery Process What happens when this disaster occursDisaster Scenario 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