AWS ElastiCache Valkey “Durability”

Valkey really, really wants to be a persistent data store.

AWS just released Valkey Durability, which is a way of transforming it from an ephemeral storage system to a persistent storage system.

Before, you just stored temporary cache data.

Now they really want you to store long-term data in there.

How? If you turn on their durability function, it will store a transaction log that you can use to rebuild the latest state.

If you switch durability on, you have 2 options:

Option 1 - Asynchronous:

This means it writes to the transaction log as soon as it can. By their measurement within 10 seconds. This is faster, but there could be data loss.

Option 2 - Synchronous: This will write to the log in real time, making it virtually impossible to have data loss. The drawback is that the extra write operation will add a few milliseconds of latency to the request.

Those are your options; weigh them out to see which one fits your use case.

Would I use Valkey for persistent data storage?

I am not at the point where I would recommend it for my client’s critical operations, but I do intend to play with it and see how it performs under pressure.

This new feature will help me sleep at night, the day we go live with Valkey as a persistent storage medium.

Would you use Valkey for persistent storage?