Which two synchronous remote replication topologies does Dell Unity XT support? (Select 2)

Question

Options

• AOne-directional
• BBi-directional
• CCascade
• DFan-out

• A
  93% (52)
• C
  5% (3)
• D
  2% (1)

Explanation

Dell Unity XT supports One-directional and Bi-directional synchronous replication because these are the only two topologies where a single replication pair can be managed with the guaranteed write-order consistency that synchronous replication demands. One-directional sends writes from a single source to a single destination, while Bi-directional allows both systems to simultaneously act as source and destination for each other - useful for active-active workloads.

Cascade (C) is incorrect because it chains replication through intermediate nodes (A→B→C), which introduces latency compounding that is incompatible with synchronous replication's requirement to confirm writes at every hop before acknowledging the host. Fan-out (D) is incorrect because it requires one source to replicate simultaneously to multiple destinations; synchronous Unity XT replication is limited to a single destination per session, making fan-out architecturally unsupported in sync mode.

Memory tip: Think "sync = simple pairs only" - One-directional (one way) and Bi-directional (both ways) both describe a single pair of systems. Cascade and Fan-out both involve three or more systems, which is the giveaway that they belong to asynchronous replication scenarios, not synchronous.

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