A client has a production data center and disaster recovery data center separated by more than 300 km. What level of recovery can they achieve by using GDPS/GM (Global Mirror)?

Question

Options

• ARPO = 0, RTO = 0
• BRPO = 0, RTO > 0
• CRPO > 0, RTO = 0
• DRPO > 0, RTO > 0

• A
  5% (1)
• B
  15% (3)
• C
  5% (1)
• D
  75% (15)

Explanation

D is correct because Global Mirror operates asynchronously - at distances over 300 km, synchronous replication is impractical due to latency, so writes are batched and shipped to the DR site with a slight delay, meaning some data can be lost (RPO > 0). Additionally, even with GDPS automation, activating the DR site, promoting secondary volumes, and restarting workloads takes time (RTO > 0).

Why the distractors fail:

• A (RPO=0, RTO=0): Impossible - zero data loss requires synchronous replication, and zero recovery time requires instant, automated failover with no steps; neither applies here.
• B (RPO=0, RTO>0): RPO=0 requires synchronous mirroring (like Metro Mirror/PPRC), which is only viable at short distances (~300 km or less) due to round-trip latency constraints - not feasible at 300+ km.
• C (RPO>0, RTO=0): GDPS automates much of the failover process but cannot achieve instantaneous recovery; there are always steps (volume promotion, application restart) that consume time.

Memory tip: "Long distance = Lag in both directions" - at 300+ km, the distance forces async replication (RPO gap) and the recovery process always takes time (RTO gap). Global Mirror = More than zero for both.

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