HP serviceguard t2808-90006 manual # cmrunpkg packagename

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Disaster Scenarios and Their Handling

 

 

Table 4-1

Disaster Scenarios and Their Handling (Continued)

 

 

 

 

Disaster Scenario

What Happens When

Recovery Process

This Disaster Occurs

 

 

 

 

 

 

In this case, the package (P1)

The package (P1) continues

In this scenario, no attempts are

runs with RPO_TARGET set to 60

to run on N1 with md0

made to repair the first failure

seconds.

 

consisting of only S1 after

until the second failure occurs.

Package P1 is running on node

the first failure

Complete the following procedure

 

to initiate a recovery:

N1. P1 uses a mirror md0

After the second failure, the

 

consisting of S1 (local to node

package does not start up

1. To recover from the first

N1, for example

 

on N2 because when it tries

failure, restore the FC links

/dev/hpdev/mylink-sde) and

to start with only S2 on N2,

between the data centers. As a

S2 (local to node N2). The first

it detects that S2 is

result, S1 is accessible from

failure occurs when all FC links

non-current for a time

N2.

between two data centers fail,

period which is greater than

2. After the FC links are

causing N1 to lose access to S2

the value of RPO_TARGET.

and N2 to lose access to S1.

 

restored, and S1 is accessible

After the package resumes

 

from N2, run the following

 

command to restart the

activity and runs for 90 seconds,

 

 

package on N2.

a second failure occurs causing

 

 

 

node N1 to fail.

 

 

# cmrunpkg <package_name>

 

 

 

When the package starts up on

 

 

 

N2, it automatically adds S1 back

 

 

 

into the array and starts

 

 

 

re-mirroring from S1 to S2. When

 

 

 

re-mirroring is complete, the

 

 

 

extended distance cluster detects

 

 

 

and accepts S1 as part of md0

 

 

 

again.

 

 

 

For the second failure, restore N1.

 

 

 

Once it is restored, it joins the

 

 

 

cluster and can access S1 and S2.

 

 

 

1. Run the following command to

 

 

 

enable P1 to run on N1:

 

 

 

# cmmodpkg -e P1 -n N1

 

 

 

 

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Chapter 4

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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 What is a Disaster Tolerant Architecture? High Availability ArchitectureNode 1 fails 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 Los Angeles Cluster New York ClusterData Cent er a Data Center B Continental ClusterBenefits of Continentalclusters Comparison of Disaster Tolerant Solutions Continental Cluster With Cascading FailoverComparison of Disaster Tolerant Cluster Solutions Attributes Extended DistanceContinentalclusters 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 ReplicationAlternative Power Sources Power Circuit 1 nodeData Center a Node 3 Power Circuit 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 Installing the Extended Distance Cluster Software Installing XDCSupported Operating Systems 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