Cloudflare has updated its DNS zone-building services, cutting median build time from 7.7 seconds to 3.3 seconds and reducing memory use on Zone Builder servers by 85%. The improvements are designed to handle a growing volume of domain changes without rebuilding more data than necessary.
A DNS zone contains a domain’s records, settings and metadata. When a customer changes a record or setting, Cloudflare distributes the update across its DNS network. The company now receives about 800 zone changes per second, compared with 250 four years ago. Some hosted domains also contain more than 20 million records, making full rebuilds demanding in both memory and network traffic.
Cloudflare previously introduced partial updates for record changes. Settings were harder to process because an event could trigger related changes across a zone, and incoming change events did not always include enough information to determine what work was required. As a result, setting updates often triggered a full rebuild.
Engineers changed the event system to include reasons and additional details, allowing updates to be classified and handled with smaller builds when possible. Changes involving apex records or metadata, as well as nameserver or wildcard updates, can now use targeted procedures. Full builds remain for cases without a partial-update method, and large zones are updated in smaller pieces. Cloudflare says these changes brought memory use down from 50–79 GB to around 7 GB.
The team also combined two schedulers and changed how they handle incoming work. The updated scheduler can group multiple changes for the same zone and process smaller jobs while a slower build is running. Previously, requests could wait behind a slow job because messages were processed in sequence, creating queues that were completed in bursts. Cloudflare says the revised approach improves concurrency and allows updates to be processed more steadily.
Sources: Tom's Hardware.