[isodude]

As noted [1] they are configurable.

  ingester:
    chunk_retain_period: 30s
    chunk_idle_period: 5m0s
    chunk_block_size: 262144
    chunk_target_size: 1572864
    chunk_encoding: gzip
    max_chunk_age: 2h0m0s

[1] https://grafana.com/docs/loki/latest/operations/storage/file...