
Disaster Scenarios and Their Handling |
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Table | Disaster Scenarios and Their Handling (Continued) | |||
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Disaster Scenario | What Happens When | Recovery Process | ||
This Disaster Occurs | ||||
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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 | |||
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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 | |
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 | ||||
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, |
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| package on N2. | |||
a second failure occurs causing |
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node N1 to fail. |
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| # cmrunpkg <package_name> | |
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| When the package starts up on | |
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| N2, it automatically adds S1 back | |
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| into the array and starts | |
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| extended distance cluster detects | |
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| and accepts S1 as part of md0 | |
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| again. | |
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| For the second failure, restore N1. | |
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| Once it is restored, it joins the | |
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| cluster and can access S1 and S2. | |
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| 1. Run the following command to | |
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| enable P1 to run on N1: | |
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| # cmmodpkg | |
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92 | Chapter 4 |