HP serviceguard t2808-90006 manual # mdadm -add /dev/md0

Page 88

Disaster Scenarios and Their Handling

 

 

Table 4-1

Disaster Scenarios and Their Handling (Continued)

 

 

 

 

Disaster Scenario

What Happens When

Recovery Process

This Disaster Occurs

 

 

 

 

 

 

A package (P1) is running on a

The package (P1) fails over

Complete the following procedure

node (Node 1). The package uses

to Node 2 and starts

to initiate a recovery:

a mirror (md0) that consists of

running with the mirror of

1. Restore data center 1, Node 1

two storage components - S1

md0 that consists of only

(local to Node 1 -

 

the storage local to node 2

and storage 1. Once Node 1 is

/dev/hpdev/mylink-sde) and

(S2).

restored, it rejoins the cluster.

S2 (local to Node 2)

 

 

Once S1 is restored, it

Data center 1 that consists of

 

becomes accessible from Node

 

2.

Node 1 and P1 experiences a

 

 

When the package failed over

failure.

 

 

NOTE: In this example, failures

 

and started on Node 2, S1 was

 

not a part of md0. As a result,

in a data center are

 

 

you need to add S1 into md0.

instantaneous. For example -

 

Run the following command to

power failure.

 

 

add S1 to md0:

 

 

 

# mdadm – -add /dev/md0

 

 

 

/dev/hpdev/mylink-sde

 

 

 

The re-mirroring process is

 

 

 

initiated. When it is complete,

 

 

 

the extended distance cluster

 

 

 

detects the added mirror half

 

 

 

and accepts S1 as part of md0.

 

 

 

2. Enable P1 to run on Node 1 by

 

 

 

running the following

 

 

 

command:

 

 

 

# 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 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
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