fsync
No restart — takes effect on reloadtuned by pgconfiguratorboolean (on/off)
Whether PostgreSQL forces data to physically reach disk — the master durability switch.
What pgconfigurator would set
32 GB · 8 vCPU · NVMe · OLTP
Computing…
Tune for your exact server → /tunecomputed in your browser · nothing uploaded
What it does
With fsync on (the default), PostgreSQL issues real disk-sync calls so committed data survives an OS crash or power loss. Turning it off lets writes stay in volatile OS cache — much faster, but a crash can leave the database silently corrupted.
How to tune it
Leave it on for any data you care about. The only legitimate time to set it off is a throwaway database you can fully rebuild — CI, a one-shot bulk import into an empty cluster — where speed matters and the data is disposable. Never off in production.
FAQ
- Is it ever safe to turn fsync off?
- Only when the entire cluster is disposable — e.g. an ephemeral CI database or a fresh import you can redo from scratch. A crash with fsync off can corrupt the whole cluster, not just lose recent commits.