Sun Cluster Geographic Edition Data Replication Guide for Hitachi TrueCopy

Validations That Occur Before a Switchover

When a switchover is initiated by using the geopg switchover command, the data replication subsystem runs several validations on both clusters. The switchover is performed only if the validation step succeeds on both clusters.

First, the replication subsystem checks that the Hitachi TrueCopy device group is in a valid aggregate device group state. Then, it checks that the local device group states on the target primary cluster, cluster-newyork, are 23, 33, 43, or 53. The local device group state is returned by the pairvolchk -g device-group-name -ss command. These values correspond to a PVOL_PAIR or SVOL_PAIR state. The Hitachi TrueCopy commands that are run on the new primary cluster, cluster-newyork, are described in the following table.

Table 3–1 Hitachi TrueCopy Switchover Validations on the New Primary Cluster

Aggregate Device Group State 

Valid Device Group State on Local Cluster 

Hitachi TrueCopy Switchover Commands That Are Run on cluster-newyork




Regular primary 

23, 43 

No command is run, because the Hitachi TrueCopy device group is already in the PVOL_PAIR state.

Regular secondary 

33, 53 

horctakeover -g dg [-t]

The-t option is specified when the fence_level of the Hitachi TrueCopy device group is async. The value is calculated as 80% of the Timeout property of the protection group. For example, if the protection group has a Timeout of 200 seconds, the value of -t used in this command is 80% of 200 seconds, or 160 seconds.

Takeover primary 



Takeover secondary