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Hard disk drives and solid-state drives are common types of persistent storage. This can be in the form of file, block or object storage. On the other hand, RAM and cache are typically non-persistent, and data is erased when power is turned off. However, certain types such as non-volatile RAM and flash-based RAM are persistent. Persistence is beneficial so that in the event of a crash or reboot, data is not lost.
In containerization, persistent storage refers to storage volumes -- usually associated with stateful applications such as databases -- that remain available beyond the life of individual containers. Persistent storage volumes can be contrasted with ephemeral storage volumes that live and die with containers and are associated with stateless apps.