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Question 1: An organization performs copy on first access (CoFA) replication to create a local replica of application data. To perform a successful restore, what should be considered?

A. Source devices must be healthy

B. Save location size must be larger than the size of all source devices

C. Save location size must be equal to the size of all source devices

D. All changes to the source and replica must be discarded before the restore starts

Answer: A Explanation: Replication: Restore & Restart Considerations Local replicas are used to restore data to production devices. Alternatively, applications can be restarted using the consistent point-in-time replicas. Replicas are used to restore data to the production devices if logical corruption of data on production devices occurs—that is, the devices are available but the data on them is invalid.

Examples of logical corruption include accidental deletion of data (tables or entries in a database),incorrect data entry, and incorrect data updates. Restore operations from a replica are incremental and provide a small RTO. In some instances, the applications can be resumed on the production devices prior to the completion of the data copy. Prior to the restore operation, access to production and replica devices should be stopped.

Production devices might also become unavailable due to physical failures, such as production server or physical drive failure. In this case, applications can be restarted using the data on the latest replica. As a protection against further failures, a “Gold Copy” (another copy of replica device) of the replica device should be created to preserve a copy of data in the event of failure or corruption of the replica devices. After the issue has been resolved, the data from the replica devices can be restored back to the production devices. 

Full-volume replicas (both full-volume mirrors and pointer-based in Full Copy mode) can be restored to the original source devices or to a new set of source devices. Restores to the original source devices can be incremental, but restores to a new set of devices are fullvolume copy operations.

In pointer-based virtual and pointer-based full-volume replication in CoFA mode, access to data on the replica is dependent on the health and accessibility of the source volumes. If the source volume is inaccessible for any reason, these replicas cannot be used for a restore or a restart operation.

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