Durable Storage

In Upstash, persistence is always enabled, setting it apart from other Redis offerings. Every write operation is consistently stored in both memory and the block storage provided by cloud providers, such as AWS’s EBS. This dual storage approach ensures data durability. Read operations are optimized to first check if the data exists in memory, facilitating faster access. If the data is not in memory, it is retrieved from disk. This combination of memory and disk storage in Upstash guarantees reliable data access and maintains data integrity, even during system restarts or failures.

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Multi Tier Storage

Upstash keeps your data both in memory and disk. This design provides:

• Data safety with persistent storage
• Low latency with in memory access
• Price flexibility by using memory only for active data

In Upstash, an entry in memory is evicted if it remains idle, meaning it has not been accessed for an extended period. It’s important to note that eviction does not result in data loss since the entry is still stored in the block storage. When a read operation occurs for an evicted entry, it is efficiently reloaded from the block storage back into memory, ensuring fast access to the data. This eviction mechanism in Upstash optimizes memory usage by prioritizing frequently accessed data while maintaining the ability to retrieve less frequently accessed data when needed.