Question: What is the Redis replication timeout and how can it be set?

Answer

Redis replication timeout sets the maximum amount of time the master waits for a ping response from its slave before dropping the connection. This configuration is critical to prevent potential data loss or stale reads in case of network issues or unresponsive slaves.

The repl-timeout setting in the Redis configuration file controls this value, and it's specified in seconds. By default, it's set to 60 seconds. You can change it as follows:

# In your redis.conf file
repl-timeout 120

This sets the replication timeout to 120 seconds. Save and exit the file, then restart the Redis server for the changes to take effect.

You can also modify this setting at runtime using the CONFIG SET command:

# Via Redis CLI
redis-cli CONFIG SET repl-timeout 120

Be cautious when adjusting this value. Setting it too low may lead to unnecessary disconnections due to transient network issues, while setting it too high may delay the detection of genuine problems with slave nodes.