Functions of a HyperMetro Consistency Group
A consistency group ensures that the read/write control policies of the multiple LUNs on a storage system are consistent.
In medium- and large-size databases, the user data and logs are stored on different LUNs. If data on any LUN is lost or becomes inconsistent in time with the data on other LUNs, data on all of the LUNs becomes invalid. Creating a HyperMetro consistency group for these LUNs can preserve the integrity of their data and guarantee write-order fidelity.
The following compares data synchronizations with and without a consistency group.
Without a HyperMetro Consistency Group
If LUNs are not added to a HyperMetro consistency group, there is a high probability of data loss on these LUNs, as shown in Figure 2-3.
With a HyperMetro Consistency Group
If LUNs are added to a HyperMetro consistency group, no data is lost, as shown in Figure 2-4.
