The way data gets stored in Prometheus, as we can see in the following example, is organized into a series of directories (blocks) containing the data chunks, the LevelDB index for that data, a meta.json file with human-readable information about the block, and tombstones for data that's no longer required. Each one of these blocks represents a database.

At the top level, you can also see the WAL for the data that's not been flushed into its own chunk yet:

...
├── 01CZMVW4CB6DCKK8Q33XY5ESQH
│   ├── chunks
│   │ └── 000001
│   ├── index
│   ├── meta.json
│   └── tombstones
├── 01CZNGF9G10R2P56R9G39NTSJE
│   ├── chunks
│   │ └── 000001
│   ├── index
│   ├── meta.json
│   └── tombstones
├── 01CZNGF9ST4ZNKNSZ4VTDVW8DH
│   ├── chunks
│   │ └── 000001
│   ├── index
│   ├── meta.json
│   └── tombstones
├── lock
└── wal
    ├── 00000114
    ├── 00000115
    ├── 00000116
    ├── 00000117
    └── checkpoint.000113
        └── 00000000