Why it matters
For time-series workloads with millions of writes per second and single-digit-ms read latency requirements, Bigtable is often the only viable managed choice on GCP.
The architecture
Bigtable data model is similar to HBase: rows keyed by lexicographic row keys, column families containing many columns, cells with timestamps and versions.
An instance has nodes (compute+storage units). Nodes scale up for more throughput; storage scales independently. Zonal or replicated clusters for HA and geo-distribution.
How it works end to end
Row key design is critical. Monotonic keys hit one node; well-distributed keys spread across nodes. Salting or hashing helps for hot writes.
Column families group columns by access pattern and TTL. Tables have limited families (default 100).
Bigtable integrates with HBase API for compatibility, and with BigQuery via federated queries.