Database / ValKey Interview questions

What is the difference between synchronous and asynchronous replication in Valkey?

Valkey defaults to asynchronous replication, and offers the WAIT command as an opt-in way to approximate stronger durability on specific writes.

Default (Async)	WAIT-backed
Client gets a reply immediately; replicas catch up in the background	Client blocks until N replicas acknowledge the write
Small window of possible lost writes if the primary crashes	Reduced loss risk, since replicas are confirmed first
Lower per-write latency	Added latency while waiting for acknowledgments
Best-effort durability guarantee	Stronger, but not a strict two-phase-commit guarantee, and can time out

Take quiz

By default, Valkey replication is... fully synchronous with a built-in two-phase commit

✗ Try again if not.

asynchronous

✓ Correct! Well done.

disabled unless AOF is on

✗ Try again if not.

quorum-based like a Raft consensus log

✗ Try again if not.

Using WAIT to approximate synchronous durability comes at the cost of... permanently disabling AOF

✗ Try again if not.

added write latency while waiting for replica acknowledgments

✓ Correct! Well done.

removing the need for persistence

✗ Try again if not.

automatically converting the deployment to Cluster mode

✗ Try again if not.

More Related questions...

What is Valkey? What is the purpose of Valkey? What are the data types supported by Valkey? How do you install Valkey on a Linux server? Define Valkey persistence? What is RDB persistence in Valkey? What is AOF persistence in Valkey? Describe Valkey replication? List the eviction policies supported by Valkey? What is the purpose of Valkey Sentinel? What is Valkey Cluster? How do you apply a TTL to a key in Valkey? What is the purpose of the valkey.conf configuration file? How do you use the Valkey CLI to connect to a remote, password-protected server? Explain the basic architecture of a Valkey server? Why was Valkey created? Why do we use Valkey instead of Redis? What is the difference between Valkey and Redis? How does Valkey Cluster achieve horizontal scaling through hash slots? How does Valkey handle automatic failover in Sentinel mode? When should you choose Valkey Cluster over Sentinel? What is the difference between RDB and AOF persistence? How can you optimize memory usage in Valkey? How do you troubleshoot high latency in a Valkey deployment? Explain the lifecycle of a command from a Valkey client to execution and response? Explain the execution flow of primary-replica replication in Valkey? Explain the internal working of the Valkey single-threaded event loop? Why doesn't Valkey execute commands using multiple threads by default? What happens when a primary node fails in a Valkey Cluster? Which is better and why: Valkey Cluster or client-side sharding? How does Valkey implement publish/subscribe messaging? What is the difference between LPUSH and RPUSH? How do you use Valkey Streams for event processing? What are Valkey modules and how do you load one? How does Valkey handle expired key deletion internally? What is the difference between Valkey and Memcached? How do you secure a Valkey deployment in production? What is the role of ACLs in Valkey? How does Valkey handle memory fragmentation? What is the difference between WAIT and replica acknowledgment in Valkey? How do you perform a zero-downtime Valkey version upgrade? Explain the internal working of Valkey's hash slot mechanism in cluster mode? How do you troubleshoot a split-brain scenario with Valkey Sentinel? Explain the difference between Valkey Cluster mode and standalone mode? How does Valkey achieve high availability? What is the difference between synchronous and asynchronous replication in Valkey? How do you monitor Valkey performance in production? Explain the internal working of Valkey's LRU and LFU eviction algorithms? Why should you avoid running the KEYS command in production? How does Valkey's multi-threaded I/O model improve throughput over classic single-threading?

Show more question and Answers...

Integration

	Interviews Questions Java Spring Hibernate DevOps Testing API BigData Web Erlang AI Database Integration Cloud Python Scala Tools Golang SAP	About Javapedia.net Javapedia.net is for Java and J2EE developers, technologist and college students who prepare of interview. Also this site includes many practical examples. This site is developed using J2EE technologies by Steve Antony, a senior Developer/lead at one of the logistics based company. Follow Javapedia updates
	contact: javatutorials2016[at]gmail[dot]com
Kindly consider donating for maintaining this website. Thanks.
	Copyright © 2026, javapedia.net, all rights reserved. Privacy Policy · Terms of Service.

Database / ValKey Interview questions

What is the difference between synchronous and asynchronous replication in Valkey?

Comments & Discussions

Recently added questions