PCDE Practice Question: Manage a solution that can span multiple database technologies
A company runs Memorystore for Redis with a Standard tier instance. They want to scale to higher throughput and memory capacity beyond the current tier limits. Which TWO actions should they take?
⚠ Common exam trap
The PCDOE exam often tests the distinction between vertical scaling (upgrading tier) and horizontal scaling (sharding), and candidates may mistakenly think that increasing maxmemory or adding replicas can overcome tier limits, when in fact replicas do not increase total memory capacity and maxmemory is bounded by the instance's physical RAM.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Enable Redis Cluster to shard data across multiple nodes.
Redis Cluster shards data across multiple nodes, allowing horizontal scaling beyond the limits of a single Standard tier instance. This enables higher throughput and memory capacity by distributing the dataset across multiple primary nodes, each handling a subset of the keyspace.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Switch from HDD to SSD storage.
Why it's wrong here
Memorystore uses memory, not disk storage types.
- ✓
Enable Redis Cluster to shard data across multiple nodes.
Why this is correct
Redis Cluster allows horizontal scaling.
- ✗
Add a cross-region replica to increase read capacity.
Why it's wrong here
Cross-region replicas are not supported; replicas are within same region.
- ✗
Increase the maxmemory setting beyond the tier limit.
Why it's wrong here
maxmemory cannot exceed the tier's memory allocation.
- ✓
Upgrade to a larger tier (e.g., from M5 to M10).
Why this is correct
Vertical scaling increases capacity.
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Same concept, more angles
2 more ways this is tested on PCDE
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. A team is managing a Memorystore for Redis instance that needs to scale to handle increased traffic. They want to ensure high availability and the ability to distribute data across multiple nodes. Which three actions should they take? (Choose THREE.)
hard- A.Use Cloud Storage snapshots for persistence
- ✓ B.Enable Redis Cluster on the instance to shard data across multiple nodes
- ✓ C.Upgrade the instance to a higher memory size by changing the tier
- ✓ D.Create a read replica in a different zone for high availability
- E.Enable AOF persistence
Why B: Memorystore for Redis offers vertical scaling (changing tier) and horizontal scaling via Redis Cluster (enabling clustering). For HA, they can create a standard tier instance with replication (a read replica).
Variation 2. You have a Memorystore for Redis instance used as a cache. You need to scale it to handle increased load. The current instance is Basic Tier with 2 GB memory. Which TWO actions can you take to scale the instance? (Choose two.)
medium- ✓ A.Vertically scale the instance by increasing its memory size or changing to a higher-tier (e.g., Standard Tier).
- B.Create additional instances and implement client-side sharding.
- C.Change the eviction policy to noeviction to allow more data.
- D.Add read replicas to offload read traffic.
- ✓ E.Enable Redis Cluster to horizontally scale across multiple shards.
Why A: Memorystore supports vertical scaling by increasing memory size or changing to a higher tier (e.g., Basic to Standard, or Standard to Standard with more memory) – this is option A. Horizontal scaling is achieved by enabling Redis Cluster, which automatically shards data across multiple nodes – this is option E. Option B (creating additional instances with client-side sharding) is not a supported scaling method for Memorystore because it requires manual management and is not integrated with the service. Option C (changing eviction policy to noeviction) does not scale the instance and risks data loss when memory is full. Option D (adding read replicas) is available only in Standard Tier, but it offloads read traffic, not scales the cache capacity.
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This PCDE practice question is part of Courseiva's free Google Cloud certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the PCDE exam.