Production usage

Get your StackExchange.Redis app ready for production

This guide offers recommendations to get the best reliability and performance in your production environment.

Checklist

Each item in the checklist below links to the section for a recommendation. Use the checklist icons to record your progress in implementing the recommendations.

- [ ] [Event handling](#event-handling)
- [ ] [Timeouts](#timeouts)
- [ ] [Exception handling](#exception-handling)
- [ ] [Retries](#retries)

Recommendations

The sections below offer recommendations for your production environment. Some of them may not apply to your particular use case.

Event handling

The ConnectionMultiplexer class publishes several different types of events for situations such as configuration changes and connection failures. Use these events to record server activity in a log, which you can then use to monitor performance and diagnose problems when they occur. See the StackExchange.Redis Events page for the full list of events.

Server notification events

Some servers (such as Azure Cache for Redis) send notification events shortly before scheduled maintenance is due to happen. You can use code like the following to respond to these events (see the StackExchange.Redis docs for the full list of supported events). For example, you could inform users who try to connect that service is temporarily unavailable rather than letting them run into errors.

using StackExchange.Redis;

ConnectionMultiplexer muxer = ConnectionMultiplexer.Connect("localhost:6379");

muxer.ServerMaintenanceEvent += (object sender, ServerMaintenanceEvent e) => {
    // Identify the event and respond to it here.
    Console.WriteLine($"Maintenance event: {e.RawMessage}");
};

Timeouts

If a network or server error occurs while your code is opening a connection or issuing a command, it can end up hanging indefinitely. To prevent this, StackExchange.Redis sets timeouts for socket reads and writes and for opening connections.

By default, the timeout is five seconds for ConnectTimeout and SyncTimeout, and AsyncTimeout uses the same value as SyncTimeout. You can set the time (in milliseconds) separately for connections and commands using these configuration options:

var muxer = ConnectionMultiplexer.Connect(new ConfigurationOptions {
    ConnectTimeout = 10000,  // 10 seconds for connections.
    SyncTimeout = 10000,     // 10 seconds for synchronous commands.
    AsyncTimeout = 10000     // 10 seconds for asynchronous commands.
        .
        .
});

var db = muxer.GetDatabase();

The default timeouts are a good starting point, but cloud applications may need longer timeouts to handle transient network or server delays. Shorter timeouts do not make commands run faster; they only fail sooner. Tune these values to improve reliability and resilience for your workload.

Exception handling

Redis handles many errors using return values from commands, but there are also situations where exceptions can be thrown. In production code, you should handle exceptions as they occur. The list below describes some the most common Redis exceptions:

• RedisConnectionException: Thrown when a connection attempt fails.
• RedisTimeoutException: Thrown when a command times out.
• RedisCommandException: Thrown when you issue an invalid command.
• RedisServerException: Thrown when you attempt an invalid operation (for example, trying to access a stream entry using an invalid ID).

See Error handling for more information on handling exceptions.

Retries

During the initial ConnectionMultiplexer.Connect() call, StackExchange.Redis will repeat failed connection attempts. By default, it will make three attempts, but you can configure the number of retries using the ConnectRetry configuration option.

You should also consider the AbortOnConnectFail option. If this is true, Connect() fails when it can't connect after the configured number of attempts. If it is false, Connect() can return a disconnected multiplexer and keep trying to connect in the background, which is helpful in cloud environments where dependencies may come online out of sequence. The default is true, except for Azure endpoints, where it defaults to false.

var muxer = ConnectionMultiplexer.Connect(new ConfigurationOptions {
    ConnectRetry = 5,  // Retry up to five times.
    AbortOnConnectFail = false,
        .
        .
});

After the initial Connect() call is successful, StackExchange.Redis will automatically attempt to reconnect if the connection is lost. You can specify a reconnection strategy with the ReconnectRetryPolicy configuration option. StackExchange.Redis provides two built-in classes that implement reconnection strategies:

• ExponentialRetry: (Default) Uses an exponential backoff strategy, where you specify an increment to the delay between successive attempts and, optionally, a maximum delay, both in milliseconds.
• LinearRetry: Uses a linear backoff strategy with a fixed delay between attempts, in milliseconds.

The example below shows how to use the ExponentialRetry class:

var muxer = ConnectionMultiplexer.Connect(new ConfigurationOptions {
    // 500ms increment per attempt, max 2000ms.
    ReconnectRetryPolicy = new ExponentialRetry(500, 2000),  
        .
        .
});

You can also implement your own custom reconnect policy by creating a class that implements the IReconnectRetryPolicy interface.

StackExchange.Redis doesn't provide an automated retry mechanism for commands. For command retries, use a bounded retry strategy in your application code and retry only transient failures such as RedisConnectionException and RedisTimeoutException. Many .NET apps use a resilience library such as Polly to manage retry delays, backoff, jitter, and retry limits instead of writing retry loops by hand.