For years, “Bronze” quietly became a parking lot for periodic snapshots: copy a slice from the source every hour/day, write new files, repeat. It worked, but it was noisy and expensive—lots of hot storage, lots of ingest compute, and a tendency to let “temporary” landing data turn into de‑facto history.
Fabric upends that with two primitives that encourage Zero Unmanaged Copies:
- Mirroring: a service‑managed, near–real‑time replica of your database/tables into OneLake, with replication compute included and a capacity‑based allowance of free mirrored storage (1 TB per CU; e.g., an F64 includes 64 TB just for mirrored replicas). You still pay for downstream query/transform compute, but not for the continuous ingest job itself. Retention for mirrored data is explicitly managed and—by default for new mirrors since mid‑June 2025—kept lean (1 day) unless you raise it.
- Shortcuts: pointers that let Fabric read in place from ADLS/S3/other OneLake locations (and even across tenants via External Data Sharing, which creates a shortcut in the consumer’s tenant rather than duplicating data). That means zero OneLake bytes for the data itself; you pay storage where the data already lives, and Fabric charges only for the compute you use to read/transform it.
Add Real‑Time Intelligence/Eventhouse or Eventstreams, and “Bronze” becomes the live edge: the freshest, governed view of your sources—either replicated (Mirroring) or virtualized (Shortcuts)—instead of a pile of periodic copies.
Continue reading “Bronze Is Live Now: what Mirroring + Shortcuts really change about cost, archives, and getting to Silver”