Consistency | Tigris Object Storage Documentation
On this page
Tigris provides strong consistency guarantees for all object storage operations. Every read returns the most recent successful write, there are no stale reads within the consistency boundary defined by your bucket's location type.
How Consistency Works
Data consistency depends on where replicas exist relative to the request origin:
- Same-region requests: All location types provide strong consistency. A read issued from the same region as the data will always return the latest write.
- Cross-region requests: The consistency guarantee depends on the location type.
Consistency by Location Type
| Location Type | Same-region | Cross-region | How it works |
|---|---|---|---|
| Global | Strong | Eventual | Cross-region reads may serve a cached or on-demand copy that is eventually consistent. |
| Multi-region | Strong | Strong | Any region can serve a strongly consistent read. |
| Dual-region | Strong | Eventual | Reads from within same region as the data are strongly consistent. Reads from outside are eventually consistent. |
| Single-region | Strong | Strong | All requests, regardless of origin, are routed to one region, providing strong consistency globally. |
What Strong Consistency Means in Practice
When Tigris guarantees strong consistency for a request, the following holds:
- Read-after-write: A GET immediately after a PUT returns the new object.
- Read-after-delete: A GET immediately after a DELETE returns a 404.
- Read-after-update: A GET immediately after an overwrite returns the new version.
- List-after-write: A LIST immediately after a PUT includes the new object.
- Conditional operations: Compare-and-set (If-Match, If-None-Match) and other conditional operations always evaluate against the latest state.
When consistency is eventual (cross-region reads for Global and Dual-region buckets), there is a brief window where a read may return a previous version of the object. The replication lag is typically sub-second.
Choosing a Location Type for Consistency
If your application requires strong consistency for every read regardless of where the request originates, choose Multi-region or Single-region.
If your application can tolerate brief cross-region staleness in exchange for lower latency or global data distribution, Global is a good choice.
For most workloads that need both geographic redundancy and strong global consistency, we recommend Multi-region. It provides the highest availability, and strong consistency globally.
For full details on all location types, including data placement, availability, and consistency, see Bucket Locations.