Share via

Migration from Azure Cosmos DB for PostgreSQL cluster to Azure Database for PostgreSQL (Elastic Cluster)

Dhanushree R 40 Reputation points
2026-06-02T08:13:57.17+00:00

We are evaluating migration from Azure Cosmos DB for PostgreSQL to Azure Database for PostgreSQL Elastic Cluster.

Our cluster configuration is:

  • 1 Coordinator Node (8 vCores, 512 GB storage)
  • 7 Worker Nodes (8 vCores, 4 TB storage per worker)

The Migration blade shows the following error:

Cluster is not eligible for migration.

  • Migration for multi-node clusters is not currently supported.
  • Migration with the current disk configuration is not supported.

Could you please clarify:

  1. Is support for migrating multi-node Cosmos DB for PostgreSQL clusters planned in the future? If yes, is there any estimated timeline?
  2. If multi-node migration will not be supported, what is the recommended migration approach for large, distributed clusters?
  3. What does "Migration with the current disk configuration is not supported" mean in this scenario?

Any guidance would be appreciated.

Azure Database for PostgreSQL
0 comments

Answer accepted by question author

Manoj Kumar Boyini 16,150 Reputation points Microsoft External Staff Moderator
2026-06-02T12:11:08.1233333+00:00

Hi @Dhanushree R

Regarding the migration from Azure Cosmos DB for PostgreSQL to Azure Database for PostgreSQL Elastic Cluster:

  • Migration support is applicable for clusters running PostgreSQL 16 with Citus 12.1.
  • Support for multi-node cluster migrations is planned and is currently targeted for mid-July 2026.
  • Support for multi-node migrations with Microsoft Entra ID authentication is also currently targeted for mid-July 2026.
  • For clusters showing the message "Migration with the current disk configuration is not supported", the required disk configuration updates are expected to be applied automatically through upcoming platform maintenance activities. While we do not have a specific ETA to share, the expectation is that these updates will be completed by the time multi-node migration support becomes available.
  • We recommend rechecking the migration eligibility after the maintenance activities have been applied. If the disk configuration message continues to appear afterward, please open a support ticket for further investigation.

References: https://learn.microsoft.com/azure/cosmos-db/postgresql/migrate-postgresql-elastic-cluster

Please let us know if you have any questions or concerns.

Was this answer helpful?

2 people found this answer helpful.
0 comments

2 additional answers

Sort by: Most helpful
Most helpful Newest Oldest
  1. kagiyama yutaka 3,510 Reputation points
    2026-06-02T11:02:02.32+00:00

    I think multi‑node Cosmos DB for PostgreSQL clusters are not eligible for the migration tool, the disk‑config message has no public detail, and the right step is to stop at the Migration blade and continue with Azure Support.

    Was this answer helpful?

    0 comments

  2. AI answer

    2026-06-02T08:14:11.36+00:00
    1. The provided information only states that Azure Cosmos DB for PostgreSQL is on a retirement path and recommends migrating PostgreSQL workloads to Azure Database for PostgreSQL with Elastic Cluster, using the dedicated migration tool exposed in the Migration tab. It does not state that multi-node (multi-worker) Cosmos DB for PostgreSQL clusters are supported by this automated migration tool today, and it does not provide any roadmap or timeline for adding support. No forward-looking commitments or dates are documented.
    2. The documented migration approach is a dedicated migration tool that:
      • Takes a snapshot from the Cosmos DB for PostgreSQL (CPG) cluster.
      • Creates a new data disk on Azure Database for PostgreSQL Flexible Server (Flex) from that snapshot.
      • Mounts this disk as the primary data disk of the target Elastic Cluster.
      • Copies delta files (extensions, PostgreSQL and extension configs, certificates, archive logs, etc.) from the original Flex /datadrive into the new disk.
      This approach is designed to minimize downtime and avoid dependence on network throughput by working at the disk/snapshot level rather than row-by-row logical migration. However, the context does not describe an alternative, officially recommended procedure specifically for large, distributed multi-node clusters when the automated migration blade reports that the cluster is not eligible. It only states that for PostgreSQL workloads, the target service should be Azure Database for PostgreSQL with Elastic Cluster and that the migration guidance is in the same article that describes the migration tool.
    3. The migration description explains that the tool relies on taking a snapshot of the Cosmos DB for PostgreSQL cluster and using it as the primary data disk for the Elastic Cluster. The error message “Migration with the current disk configuration is not supported” indicates that the current storage layout of the Cosmos DB for PostgreSQL cluster does not meet the assumptions of this disk-snapshot-based migration approach. In other words, the migration tool expects a specific disk configuration that it can snapshot and attach directly to the Elastic Cluster. If the cluster’s disk configuration differs from what the tool supports (for example, size/layout/underlying Flex disk assumptions), the automated migration cannot proceed and the portal reports that the cluster is not eligible. The documentation does not provide further detail on which exact disk configurations are supported or unsupported beyond describing that the migration is implemented by snapshotting the CPG cluster’s data disk and mounting it on the Elastic Cluster.

    References:

    AI-generated content may be incorrect. Read our transparency notes for more information.

    Was this answer helpful?

Your answer

Answers can be marked as 'Accepted' by the question author and 'Recommended' by moderators, which helps users know the answer solved the author's problem.