PostgreSQL VPS Requirements: RAM, shared_buffers, Connections & NVMe
PostgreSQL VPS sizing guide covering RAM, shared_buffers, query memory, connections, storage latency, WAL, backups and dedicated-server upgrade signals.
Direct answer: PostgreSQL VPS requirements depend on working-set size, connection count, query memory, WAL/write rate and storage latency. Production sizing should leave memory for both PostgreSQL and the operating-system page cache.
PostgreSQL 18 documentation notes that on a dedicated database server with 1 GB or more RAM, around 25% of memory is a reasonable starting point for shared_buffers, while also noting that PostgreSQL relies on OS caching and workload-specific tuning.
At a glance
| Question | Practical answer |
|---|---|
| Small development DB | 2–4 GB can be workable for light datasets and low concurrency. |
| Small production DB | 8 GB is a practical starting discussion when the active dataset is modest. |
| Growing production | 16–32 GB+ as cache, queries and connections expand. |
| Storage priority | Measure p95/p99 latency and WAL/checkpoint behaviour. |
Memory is more than shared_buffers
PostgreSQL also uses per-query and maintenance memory, while the OS needs cache. A high work_mem multiplied across many concurrent operations can consume far more RAM than expected.
Connections and pooling
Large connection counts consume resources. Use pooling when application architecture creates many mostly idle connections, and monitor active sessions, locks and long queries.
Storage and WAL
Database performance is sensitive to commit latency, checkpoints and WAL writes. NVMe helps, but bad queries or excessive synchronous writes can still dominate. Measure I/O wait and database-level metrics.
Backup and restore
Keep logical or physical PostgreSQL backups according to RPO, plus an independent copy outside the live VPS. Test a restore including application permissions and connectivity.
Buyer / deployment checklist
- Measure active dataset and growth.
- Track cache hit rate and slow queries.
- Check connection count and pooling.
- Watch shared_buffers/work_mem in context.
- Measure storage latency.
- Plan WAL and backup growth.
- Keep off-server backups.
- Test restoration.
Frequently asked questions
Should shared_buffers use all RAM?
No. PostgreSQL also relies on OS caching and other memory areas.
Is NVMe enough to make PostgreSQL fast?
No. Query plans, indexes, memory and write patterns matter.
When should I move to dedicated?
When sustained CPU/I/O, large memory or control requirements make virtual infrastructure the constraint.
Bottom line
PostgreSQL VPS sizing should be measurement-first. Give the database enough RAM to cache useful data, keep query memory under control, watch storage latency and maintain an independent restore path.
Sources and verification
Reviewed 8 September 2026. Current pricing, stock, routes and software versions can change.
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