Which statement about snapshot rollback is true?

• A. Snapshot rollback can quickly restore data.
• B. Some data may be lost during a snapshot rollback.
• C. If there are writes to the source LUN during a snapshot rollback, the rollback is performed after the writes are complete.
• D. When no host reads or writes data, the snapshot data is rolled back to the source volume in sequence.

Answer: (A)

Snapshot rollback can quickly restore data because it doesn’t require moving a lot of data. Instead, the storage system relies on the snapshot’s preserved state and re-points the source volume to those blocks. This means the volume appears as it was at the moment of the snapshot, and the reconfiguration happens almost instantly rather than copying terabytes of data.

There’s a trade-off to keep in mind: any writes that occurred after the snapshot were not part of that saved state, so rolling back typically discards those post-snapshot changes. That’s why the operation is fast, but you may lose data that was written after the snapshot.

The other statements describe conditions or behaviors that aren’t generally how rollback works: it isn’t tied to a requirement that there be no I/O, nor does it promise to wait for ongoing writes to finish before completing, and its behavior isn’t limited to a specific sequencing of operations.