Memcached is primarily designed as an in-memory caching system and does not natively support data persistence.

External Data Source : Instead of relying solely on Memcached for data storage, applications can use Memcached as a caching layer in front of an external data source such as a relational database (e.g., MySQL, PostgreSQL) or a NoSQL database (e.g., MongoDB, Cassandra). In this setup, Memcached caches frequently accessed data from the external data source, providing fast access while the data itself remains persisted in the database.

Write-Through Cache : Implement a write-through caching strategy where data is first written to the external data source and then cached in Memcached. This ensures that data remains persisted in the database while also benefiting from fast access through Memcached. Updates and deletions to the data are also propagated to the external data source to maintain consistency.

Periodic Cache Refresh : Periodically refresh cached data from the external data source to ensure that the cache remains up-to-date with the latest data from the source. This can be done using background tasks or scheduled jobs that retrieve data from the source and store it in Memcached.

Memcached Persistence Modules : Some third-party Memcached distributions or modules offer experimental support for data persistence. These modules extend Memcached's functionality to include features such as disk-based storage or replication for persisting cached data. However, these solutions may introduce additional complexity and overhead compared to traditional caching approaches.

Data Serialization and Backup : Serialize cached data periodically and store it in external storage (e.g., file system, database) for backup and recovery purposes. While this approach does not provide real-time data persistence, it ensures that data can be restored in the event of a Memcached server failure or data loss.

External Caching Libraries : Use external caching libraries or middleware solutions that offer built-in support for data persistence and synchronization with Memcached. These libraries may provide features such as automatic data synchronization, eviction policies, and consistency guarantees across multiple cache nodes.