Figure 3 Failover Scenario with Two Arbitrators

The scenarios in Table 5 illustrate possible results if a data center or one or more nodes fail in a configuration with two arbitrators. Note that 3 of the 4 scenarios that caused a cluster halt with a single arbitrator, do not cause a cluster halt with two arbitrators.

Table 5 Node Failure Scenarios with Two Arbitrators

Failure

Quorum

Result

 

 

 

data center A (nodes 1 and 2)

4 of 6 (67%)

pkg A and B switch to data center B

 

 

 

data center A, then arbitrator 1

3 of 4 (75%)

pkg A and B switch, then no change

 

 

 

data center A and arbitrator 1

3 of 6 (50%)

cluster halts*

 

 

 

data center A, then arbitrator 1, then node 3

2 of 3 (67%)

pkg A, B, and C switch

 

 

 

 

arbitrator 1, then data center A

3 of 5

(60%)

pkg A and B switch to data center B

 

 

 

 

node 3, then data center A

3 of 5

(60%)

pkg A and B switch to data center B

 

 

 

 

data center B

4 of 6

(67%)

pkg C and D switch to data center A

 

 

 

 

third location

4 of 6

(67%)

no change

 

 

 

 

* Cluster can be manually started with the remaining node.

Worksheets

Disaster Tolerant Checklist

Use this checklist to make sure you have adhered to the disaster tolerant architecture guidelines for a two main data centers and a third location configuration.

Worksheets 31