--- title: How S3 Enables Stateless Write-Ahead Logs Despite... description: A growing pattern in database and infrastructure design uses S3 as the source of truth for write-ahead logs instead of local disk plus node replication.... canonical: https://daily.dev/posts/how-s3-enables-stateless-write-ahead-logs-despite-latency-trade-offs-rywhyjxzx twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: How S3 Enables Stateless Write-Ahead Logs Despite Latency Trade-offs | daily.dev og:description: A growing pattern in database and infrastructure design uses S3 as the source of truth for write-ahead logs instead of local disk plus node replication.... og:url: https://daily.dev/posts/how-s3-enables-stateless-write-ahead-logs-despite-latency-trade-offs-rywhyjxzx og:image: https://api.daily.dev/og/posts/RywHYJXZX.png og:image:alt: How S3 Enables Stateless Write-Ahead Logs Despite Latency Trade-offs og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # How S3 Enables Stateless Write-Ahead Logs Despite Latency Trade-offs **[Arpit Bhayani](https://daily.dev/sources/arpit-bhayani)** · 2 min read · 1 upvotes · 0 comments ## Summary A growing pattern in database and infrastructure design uses S3 as the source of truth for write-ahead logs instead of local disk plus node replication. Turbopuffer, Chroma, and WarpStream all use variants of this trick: a write is only committed once it lands in S3, letting compute nodes stay stateless and cache only in NVMe or RAM. Two S3 properties enable it - strong read-after-write consistency and conditional writes via If-None-Match, which let multiple writers order a log without leader election protocols like Raft. The trade-off is latency: a single S3 round trip takes tens of milliseconds, so systems batch writes and flush on a timer, accepting 100-200ms commit latency in exchange for not having to manage replication topology, leader failover, or disk provisioning. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Questions this post answers ### How can multiple writers coordinate an ordered write-ahead log on S3 without a leader election protocol like Raft? S3's conditional writes feature, specifically the If-None-Match header, lets multiple writers coordinate an ordered log without needing a leader election protocol. Combined with S3's strong read-after-write consistency, this allows nodes to stay stateless, caching only in NVMe or RAM, since a write is considered committed only once it lands in S3. _Engineers weighing WAL architectures can follow evolving S3-backed storage patterns on daily.dev._ ### What is the typical commit latency when using S3 as the backing store for a write-ahead log? Commit latency typically ranges from 100 to 200ms when using S3 as a write-ahead log backend. This is because a single S3 round trip takes tens of milliseconds, so systems batch writes and flush on a timer rather than writing one record per S3 call, trading latency for eliminating replication topology and leader failover concerns. _Teams evaluating S3-backed WAL trade-offs can track this design pattern on daily.dev._ ### Which databases or systems use S3 as the write-ahead log storage layer? Turbopuffer, Chroma, and WarpStream all implement versions of the same pattern, using S3 as the durable store for their write-ahead logs so that compute nodes remain stateless and any node can serve any namespace since nothing durable lives locally. _Developers comparing storage-layer designs across databases can follow these patterns on daily.dev._ ## Similar posts on daily.dev - [Every fast write moves work somewhere else](https://daily.dev/posts/every-fast-write-moves-work-somewhere-else-k4xugsl0j) · Hacker News · 0 upvotes · 0 comments - [Building a Database on S3](https://daily.dev/posts/building-a-database-on-s3-z6q1mg0wr) · Metadata · 47 upvotes · 0 comments - [Why Postgres wants NVMe on the hot path, and S3 everywhere else](https://daily.dev/posts/why-postgres-wants-nvme-on-the-hot-path-and-s3-everywhere-else-lgzx97lkb) · The New Stack · 30 upvotes · 1 comments --- Tags: [#distributed-systems](https://daily.dev/tags/distributed-systems), [#aws-s3](https://daily.dev/tags/aws-s3) [View this post on daily.dev](https://daily.dev/posts/how-s3-enables-stateless-write-ahead-logs-despite-latency-trade-offs-rywhyjxzx) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"How S3 Enables Stateless Write-Ahead Logs Despite Latency Trade-offs","url":"https://daily.dev/posts/how-s3-enables-stateless-write-ahead-logs-despite-latency-trade-offs-rywhyjxzx","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/how-s3-enables-stateless-write-ahead-logs-despite-latency-trade-offs-rywhyjxzx"},"datePublished":"2026-09-02T20:27:18.551Z","dateModified":"2026-09-03T00:35:58.468Z","description":"A growing pattern in database and infrastructure design uses S3 as the source of truth for write-ahead logs instead of local disk plus node replication....","image":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/3261bb6d4ee67dcc8b0aa276bd4f899c?_a=AQAEuop","thumbnailUrl":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/3261bb6d4ee67dcc8b0aa276bd4f899c?_a=AQAEuop","isAccessibleForFree":true,"articleSection":"Arpit Bhayani","inLanguage":"en","publisher":{"@type":"Organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180}},"author":{"@type":"Organization","name":"Arpit Bhayani","logo":"https://media.daily.dev/image/upload/s--Hd9jPPXT--/f_auto,q_auto/v1780213724/logos/arpit-bhayani?_a=BAMAMiWQ0","url":"https://daily.dev/sources/arpit-bhayani"},"commentCount":0,"discussionUrl":"https://daily.dev/posts/how-s3-enables-stateless-write-ahead-logs-despite-latency-trade-offs-rywhyjxzx","interactionStatistic":[{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":1},{"@type":"InteractionCounter","interactionType":{"@type":"CommentAction"},"userInteractionCount":0}],"keywords":"distributed-systems,aws-s3","timeRequired":"PT2M"} {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://daily.dev"},{"@type":"ListItem","position":2,"name":"Arpit Bhayani","item":"https://daily.dev/sources/arpit-bhayani"},{"@type":"ListItem","position":3,"name":"How S3 Enables Stateless Write-Ahead Logs Despite Latency Trade-offs"}]} {"@context":"https://schema.org","@type":"FAQPage","@id":"https://daily.dev/posts/how-s3-enables-stateless-write-ahead-logs-despite-latency-trade-offs-rywhyjxzx#faq","mainEntity":[{"@type":"Question","name":"How can multiple writers coordinate an ordered write-ahead log on S3 without a leader election protocol like Raft?","acceptedAnswer":{"@type":"Answer","text":"S3's conditional writes feature, specifically the If-None-Match header, lets multiple writers coordinate an ordered log without needing a leader election protocol. 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