Redis Error loading dataset in memory

This error occurs when the Redis server fails to load its persisted dataset (from an RDB snapshot or AOF file) into memory during startup, typically due to insufficient system memory (OOM) or data file corruption.

Common Causes

Insufficient available memory (RAM) to hold the dataset, triggering an Out-Of-Memory (OOM) condition.
Corrupted or incomplete RDB (dump.rdb) or AOF (appendonly.aof) persistence files.
A mismatch between the Redis version that saved the data and the version trying to load it.
The system's `overcommit_memory` setting is too restrictive, preventing Redis from allocating the necessary memory.

How to Fix

1 Check System Memory and Increase Limits

Verify available memory and adjust Redis's maximum memory configuration or provision more RAM to the host.

BASH

 $ # Check available system memory
free -h

# Check Redis maxmemory setting (in redis.conf or via CLI)
redis-cli CONFIG GET maxmemory

# Set a lower maxmemory limit if necessary (e.g., 2GB)
redis-cli CONFIG SET maxmemory 2gb
# Or, edit redis.conf: maxmemory 2gb

2 Verify and Repair Persistence Files

Check the integrity of your RDB or AOF files. You can try to repair a corrupted AOF file or use a backup RDB file.

BASH

 $ # 1. Check if Redis can check the AOF file (if AOF is enabled)
redis-check-aof --fix /var/lib/redis/appendonly.aof

# 2. Check the RDB file integrity
redis-check-rdb /var/lib/redis/dump.rdb

# 3. As a last resort, start with an empty dataset by moving the corrupt files
sudo mv /var/lib/redis/dump.rdb /var/lib/redis/dump.rdb.backup
sudo mv /var/lib/redis/appendonly.aof /var/lib/redis/appendonly.aof.backup
# Then restart Redis

3 Adjust Linux Kernel Overcommit Memory Setting

Configure the kernel to be more permissive with memory overcommit, which Redis often requires for successful fork operations during save/load.

BASH

 $ # Check current setting
cat /proc/sys/vm/overcommit_memory
# Set it to 1 (allows overcommit)
sudo sysctl vm.overcommit_memory=1
# To make it permanent, add to /etc/sysctl.conf
# vm.overcommit_memory = 1