CDCP Storage Data Center 4 — Questions and Answers
Question 1: What is the key distinction between synchronous and asynchronous storage replication?
- Synchronous replication works only within the same rack; asynchronous works across sites
- Synchronous replication confirms writes on both sites before acknowledging to the host; asynchronous does not wait (Correct answer)
- Asynchronous replication uses Fibre Channel; synchronous uses iSCSI
- Synchronous replication requires tape backup as a target
Correct answer: Synchronous replication confirms writes on both sites before acknowledging to the host; asynchronous does not wait
In synchronous replication the I/O is not acknowledged to the application until it is committed on both the primary and remote sites, ensuring zero data loss.
Question 2: Which metric defines how quickly IT systems must be restored following a disaster?
- RPO
- RTO (Correct answer)
- MTBf
- IOPS
Correct answer: RTO
RTO (Recovery Time Objective) specifies the maximum allowable time to restore a system or service after a disruption.
Question 3: In data center storage, what does IOPS measure?
- The total capacity of a storage array in terabytes
- The number of read and write operations a storage device can perform per second (Correct answer)
- The bandwidth consumed by replication traffic
- The time required to complete a full backup cycle
Correct answer: The number of read and write operations a storage device can perform per second
IOPS (Input/Output Operations Per Second) measures storage performance in terms of discrete I/O transactions completed each second.
Question 4: What is a LUN (Logical Unit Number) in SAN storage?
- A physical disk drive identified by its slot position
- A logical partition of storage presented to a host as a virtual disk (Correct answer)
- The network address of a storage controller port
- A zone group configuration in Fibre Channel
Correct answer: A logical partition of storage presented to a host as a virtual disk
A LUN is a logical address that identifies a segment of storage capacity presented by the array to a host as a mountable block device.
Question 5: Which storage technology is best suited for archival of large volumes of infrequently accessed data at the lowest cost per terabyte?
- All-flash array
- NVMe over Fabrics
- LTO Tape (Correct answer)
- 15K RPM SAS drives
Correct answer: LTO Tape
LTO tape offers the lowest cost per terabyte and very low energy consumption, making it the industry standard for long-term archival storage.
Question 6: What is the function of storage snapshots in data protection?
- To create a full byte-for-byte copy of data on a separate physical array
- To capture a point-in-time image of a volume, enabling rapid recovery to that state (Correct answer)
- To compress data before sending it to a replication target
- To encrypt data at rest using a hardware security module
Correct answer: To capture a point-in-time image of a volume, enabling rapid recovery to that state
Snapshots preserve a consistent point-in-time view of data, typically using pointer-based or copy-on-write mechanisms, allowing quick rollback without a full copy.
Question 7: What is the primary benefit of using an all-flash array (AFA) compared to a hybrid array in a data center?
- Lower cost per raw terabyte
- Consistent sub-millisecond latency and higher IOPS density (Correct answer)
- Greater sequential throughput for tape backup offload
- Simpler RAID configuration options
Correct answer: Consistent sub-millisecond latency and higher IOPS density
All-flash arrays eliminate mechanical seek time entirely, delivering consistent microsecond-to-millisecond latency and dramatically higher IOPS per rack unit.
CDCP Storage Data Center 4
What is the key distinction between synchronous and asynchronous storage replication?