Choose Cloud Spanner Backup strategy
Goal
To propose and then implement a backup strategy for spanner for use as topology service storage
Action items:
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Get security sign off on overall strategy -
Perform a restore from backup -
Calculate storage growth -
Configure backup strategy in code -
Create ADR for final decision -
Add links in topology-service-deployer once ADR is complete to terraform code to document the decisions -
Validate performance implications of backup strategy
Current proposal
- Configure production as multi region as per ADR
- Enable point in time recovery for 36 hours
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Enable daily full backups for a monthEnable incremental backups for 3 months to reduce storage costs. Incremental backups create full backups after every 13 incremental backups in the chain.
Summary Comparison of backup types
| Feature | Full Backups | Incremental Backups | PITR | Export |
|---|---|---|---|---|
| Storage Efficiency | Low | High | Low | Medium |
| Recovery Speed | Fast | Medium | Fast | Slow |
| Setup Complexity | Low | Low | Low | High |
| Data Consistency |
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| Retention Period | Up to 1 year | Up to 1 year | Up to 7 days | Unlimited |
| Cross-region Support |
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Google Cloud Spanner Backup Types Comparison
Full Backups
| Pros | Cons |
|---|---|
| Simple to understand and implement | Large storage requirements |
| Complete data snapshot at point in time | Longer backup times for large databases |
| Fast restoration process | Can only be scheduled for once every 12 hours |
| Can be created on-demand or scheduled | Limited to 1-year retention maximum |
| Highly available and encrypted |
Documentation: Create backups | Backups overview
backups can be copied to another region and databases can not be deleted while a backup exists
Incremental Backups
| Pros | Cons |
|---|---|
| Storage efficient (only changed data) | Longer recovery times if many incrementals |
| Faster than full backups | Only available via backup schedules |
| Lower resource usage during backup | |
| Reduces storage costs | |
| Can backup every 4+ hours |
Documentation: Backups overview | Backup schedules
PITR (Point-in-Time Recovery)
| Pros | Cons |
|---|---|
| Precise recovery to any point in time | Limited to 7-day retention maximum |
| Minimal data loss (microsecond granularity) | Higher storage costs for extended retention |
| Continuous data protection | Performance impact with high retention periods |
| No separate backup jobs required | To restore a full database a full backup must be performed first |
| Surgical recovery of specific data using stale reads |
Documentation: PITR overview | Recover data using PITR
Export (CSV/Avro)
https://cloud.google.com/spanner/docs/import-export-overview#compare-import-export-backup-restore
Key References:
Edited by David Leach