--- title: Migrate Db2 z/OS to Amazon Aurora PostgreSQL using AWS... description: A detailed walkthrough covers migrating an on-premises IBM Db2 database on z/OS to Amazon Aurora PostgreSQL-Compatible using AWS Database Migration Service... canonical: https://daily.dev/posts/migrate-db2-z-os-to-amazon-aurora-postgresql-using-aws-dms-and-gateway-server-fi3ut7jwo twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Migrate Db2 z/OS to Amazon Aurora PostgreSQL using AWS DMS and gateway server | daily.dev og:description: A detailed walkthrough covers migrating an on-premises IBM Db2 database on z/OS to Amazon Aurora PostgreSQL-Compatible using AWS Database Migration Service... og:url: https://daily.dev/posts/migrate-db2-z-os-to-amazon-aurora-postgresql-using-aws-dms-and-gateway-server-fi3ut7jwo og:image: https://api.daily.dev/og/posts/Fi3Ut7JwO.png og:image:alt: Migrate Db2 z/OS to Amazon Aurora PostgreSQL using AWS DMS and gateway server 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. # Migrate Db2 z/OS to Amazon Aurora PostgreSQL using AWS DMS and gateway server **[AWS Database Blog](https://daily.dev/sources/aws-database-blog)** · 14 min read · 0 upvotes · 0 comments ## Summary A detailed walkthrough covers migrating an on-premises IBM Db2 database on z/OS to Amazon Aurora PostgreSQL-Compatible using AWS Database Migration Service (DMS) paired with a Db2 gateway server running on EC2. Since DMS lacks direct connectivity to Db2 on z/OS, the EC2 instance hosts IBM Db2 Connect Server to bridge the mainframe and AWS. Steps include provisioning the EC2 gateway, installing Db2 Connect, configuring DMS replication instances and endpoints, running full-load migration tasks with LOB handling, validating row counts between source and target, and automating periodic full-load refreshes using Lambda and EventBridge schedules. Prerequisites specify Aurora PostgreSQL 17.4, AWS DMS 3.6.1, and IBM Db2 Connect Server 11.5.9. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Questions this post answers ### How do I migrate an IBM Db2 z/OS database to Amazon Aurora PostgreSQL since AWS DMS doesn't support direct connectivity to Db2 on z/OS? Deploy an EC2 instance in a private subnet as a Db2 gateway server running IBM Db2 Connect Server, which bridges the mainframe and AWS since DMS cannot connect to Db2 z/OS directly. Then create AWS DMS replication instances and source/target endpoints that route through this EC2 gateway to reach Aurora PostgreSQL, and run a full-load migration task with periodic refresh. _daily.dev surfaces migration walkthroughs like this for teams modernizing off mainframe databases onto Aurora PostgreSQL._ ### What versions of Aurora PostgreSQL, AWS DMS, and IBM Db2 Connect Server work together for a Db2 z/OS migration? A validated setup uses Aurora PostgreSQL version 17.4, AWS DMS version 3.6.1, and IBM Db2 Connect Server version 11.5.9 running on an EC2 instance with Amazon Linux 2023. A valid IBM Db2 ODBC connect license is required to download and use the Db2 Connect installer, which AWS does not host or distribute. _Developers planning a Db2 to Aurora migration can track compatible tool versions through daily.dev._ ### Why is Full LOB mode slower than limited LOB mode when migrating Db2 z/OS data with AWS DMS? Full LOB mode is slower because it is strictly bounded by Db2 z/OS limits rather than supporting unlimited object sizes, unlike limited LOB mode which caps size upfront for faster processing. Migration tasks should be configured with appropriate LOB settings and optimized table mapping before starting a Db2 z/OS to Aurora PostgreSQL migration task. _Teams tuning DMS LOB settings for mainframe migrations can find similar configuration guidance on daily.dev._ ## Similar posts on daily.dev - [How to migrate from Oracle to Amazon Aurora PostgreSQL using AWS CloudFormation \(Part 1\)](https://daily.dev/posts/how-to-migrate-from-oracle-to-amazon-aurora-postgresql-using-aws-cloudformation-part-1--rb6x7noud) · AWS Database Blog · 1 upvotes · 1 comments - [Migrating SQL Server to Aurora PostgreSQL: Solving the Real Challenges of Cloud Database Modernization](https://daily.dev/posts/migrating-sql-server-to-aurora-postgresql-solving-the-real-challenges-of-cloud-database-modernizati-fvnjvvn7l) · Security Boulevard · 0 upvotes · 0 comments - [Migrate from AIX or Windows Db2 to Amazon RDS for Db2](https://daily.dev/posts/migrate-from-aix-or-windows-db2-to-amazon-rds-for-db2-thwtomc1u) · AWS Database Blog · 1 upvotes · 0 comments - [AWS DMS Schema Conversion adds SAP \(Sybase\) ASE to PostgreSQL support with generative AI](https://daily.dev/posts/aws-dms-schema-conversion-adds-sap-sybase-ase-to-postgresql-support-with-generative-ai-6kkcht1lf) · AWS · 1 upvotes · 0 comments - [Migrate self-managed PostgreSQL to Amazon RDS using the RDS console](https://daily.dev/posts/migrate-self-managed-postgresql-to-amazon-rds-using-the-rds-console-r8vrtte1a) · AWS Database Blog · 0 upvotes · 0 comments --- Tags: [#aws](https://daily.dev/tags/aws), [#database](https://daily.dev/tags/database), [#postgresql](https://daily.dev/tags/postgresql) [View this post on daily.dev](https://daily.dev/posts/migrate-db2-z-os-to-amazon-aurora-postgresql-using-aws-dms-and-gateway-server-fi3ut7jwo) ```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":"Migrate Db2 z/OS to Amazon Aurora PostgreSQL using AWS DMS and gateway server","url":"https://daily.dev/posts/migrate-db2-z-os-to-amazon-aurora-postgresql-using-aws-dms-and-gateway-server-fi3ut7jwo","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/migrate-db2-z-os-to-amazon-aurora-postgresql-using-aws-dms-and-gateway-server-fi3ut7jwo"},"datePublished":"2026-09-30T16:50:15.429Z","dateModified":"2026-09-30T16:50:40.237Z","description":"A detailed walkthrough covers migrating an on-premises IBM Db2 database on z/OS to Amazon Aurora PostgreSQL-Compatible using AWS Database Migration Service...","image":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/b31d083f8cdbe21cb198020130ea7cd8?_a=AQAEuop","thumbnailUrl":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/b31d083f8cdbe21cb198020130ea7cd8?_a=AQAEuop","isAccessibleForFree":true,"articleSection":"AWS Database Blog","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":"AWS Database Blog","logo":"https://media.daily.dev/image/upload/s--En-avd2a--/f_auto,q_auto/v1780213446/logos/aws-database-blog?_a=BAMAMiWQ0","url":"https://daily.dev/sources/aws-database-blog"},"commentCount":0,"discussionUrl":"https://daily.dev/posts/migrate-db2-z-os-to-amazon-aurora-postgresql-using-aws-dms-and-gateway-server-fi3ut7jwo","interactionStatistic":[{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":0},{"@type":"InteractionCounter","interactionType":{"@type":"CommentAction"},"userInteractionCount":0}],"keywords":"aws,database,postgresql","timeRequired":"PT14M"} {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://daily.dev"},{"@type":"ListItem","position":2,"name":"AWS Database Blog","item":"https://daily.dev/sources/aws-database-blog"},{"@type":"ListItem","position":3,"name":"Migrate Db2 z/OS to Amazon Aurora PostgreSQL using AWS DMS and gateway server"}]} {"@context":"https://schema.org","@type":"FAQPage","@id":"https://daily.dev/posts/migrate-db2-z-os-to-amazon-aurora-postgresql-using-aws-dms-and-gateway-server-fi3ut7jwo#faq","mainEntity":[{"@type":"Question","name":"How do I migrate an IBM Db2 z/OS database to Amazon Aurora PostgreSQL since AWS DMS doesn't support direct connectivity to Db2 on z/OS?","acceptedAnswer":{"@type":"Answer","text":"Deploy an EC2 instance in a private subnet as a Db2 gateway server running IBM Db2 Connect Server, which bridges the mainframe and AWS since DMS cannot connect to Db2 z/OS directly. 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