# Apache Kvrocks — Redis-Compatible Store Built on RocksDB

> A distributed key-value store that speaks the Redis protocol but persists data on disk using RocksDB, offering Redis compatibility with lower memory costs.

## Install

Save as a script file and run:

# Apache Kvrocks — Redis-Compatible Store Built on RocksDB

## Quick Use
```bash
# Build from source
git clone https://github.com/apache/kvrocks.git
cd kvrocks && ./x.py build
# Run the server
./build/kvrocks -c kvrocks.conf
# Connect with any Redis client
redis-cli -p 6666
> SET hello world
> GET hello
```

## Introduction
Apache Kvrocks is a distributed key-value store that implements the Redis wire protocol on top of RocksDB. It stores data on disk rather than entirely in memory, making it a cost-effective alternative for workloads that need Redis compatibility but have data sets larger than available RAM.

## What Apache Kvrocks Does
- Speaks the Redis RESP protocol so existing Redis clients and libraries work without changes
- Stores data on SSD or HDD via RocksDB, reducing memory requirements by orders of magnitude
- Supports most Redis data structures: strings, hashes, lists, sets, sorted sets, and streams
- Provides cluster mode with hash-slot-based sharding compatible with Redis Cluster clients
- Offers namespace-based multi-tenancy for isolating workloads on a single instance

## Architecture Overview
Kvrocks uses a multi-threaded architecture with an event-driven network layer that handles Redis protocol parsing. Commands are translated into RocksDB operations through an encoding layer that maps Redis data structures to key-value pairs on disk. A WAL-based replication mechanism supports leader-follower setups, and cluster mode distributes hash slots across multiple Kvrocks nodes using a Raft-based metadata store.

## Self-Hosting & Configuration
- Build from source with CMake or download pre-built binaries for Linux
- Edit kvrocks.conf to set the listening port, data directory, and RocksDB tuning parameters
- Enable cluster mode by setting cluster-enabled to yes and configuring node topology
- Set up replication with the slaveof command, same as Redis
- Use namespaces to partition data between different applications on one instance

## Key Features
- Drop-in Redis replacement for most commands and data structures
- Disk-based storage that handles data sets far exceeding available memory
- Built-in cluster mode with automatic slot migration and rebalancing
- Namespace isolation for multi-tenant deployments
- Lua scripting and pub/sub support compatible with Redis semantics

## Comparison with Similar Tools
- **Redis** — in-memory, fast but expensive at scale; Kvrocks trades some latency for much lower memory cost
- **KeyDB** — multi-threaded Redis fork, still in-memory; Kvrocks is disk-based
- **DragonflyDB** — high-performance in-memory store; Kvrocks targets large data on disk
- **Valkey** — Redis-compatible fork with community governance; Kvrocks differs architecturally by using RocksDB
- **Garnet** — Microsoft's cache-store in C#; Kvrocks is C++ on RocksDB with Apache governance

## FAQ
**Q: Is Kvrocks slower than Redis?**
A: Read and write latency is higher than in-memory Redis because data goes through RocksDB on disk. For many workloads, the latency difference is acceptable, especially on SSDs.

**Q: Which Redis commands are not supported?**
A: Most commands are supported. Some advanced features like Redis modules and certain cluster management commands may not be available. The documentation lists specific gaps.

**Q: Can I migrate from Redis to Kvrocks without downtime?**
A: Yes. You can set Kvrocks as a replica of a Redis instance to sync data, then promote Kvrocks and redirect clients.

**Q: Does Kvrocks support persistence and backups?**
A: Data is always persisted via RocksDB. Backups can be taken using RocksDB checkpoints or filesystem snapshots.

## Sources
- https://github.com/apache/kvrocks
- https://kvrocks.apache.org/

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Source: https://tokrepo.com/en/workflows/asset-bdee3242
Author: Script Depot