Over the years, Db2 pureScale has proven itself as a highly resilient and scalable architecture. However, moving between pureScale and non-pureScale environments and vice-versa, especially across Db2 versions is not as straightforward as many assume. This blog walks through what actually works, what doesn’t, and what changed in Db2 12.1.3, based on real-world operational experience.
Db2 11.5 and earlier versions enforce a strict topology rule during database restore operations. Restore across versions (for example Db2 11.1 to Db2 11.5) must be the same topology, which means both pureScale with same number of members, or both non-pureScale. Otherwise, the Restore will fail with SQL1564N reason code 8.
SQL1564N The restore or rollforward operation did not complete successfully because the specified operation is not supported.
Reason Code 8
A down-level image can be restored only when both of the following conditions are satisfied:
- The source topology matches the target topology.
- The source instance type matches the target instance type.
From Db2 12.1, there have been incremental changes.
Supported Direct Conversion Paths (High Level)
Scenario 1: Db2 11.1 non-pureScale → Db2 11.5/<12.1.3 pureScale
Db2 11.5 non-pureScale → <Db2 12.1.3 pureScale
This is one of the most common upgrade paths, and it cannot be done in a single step. Both the Db2 version and topology change, so the migration must be split into two controlled phases.
Option A: Convert topology first, then upgrade
Step 1 – Convert 11.1/11.5 non-pureScale → 11.1/11.5 pureScale
This step changes topology only. High-level flow:
- Take a backup from the source non-pureScale system
- Restore it into the target pureScale environment
- Run db2CheckSD
- Validate that all members are active
At this point, the database is still Db2 11.1/11.5 but now runs on pureScale.
Step 2 – Upgrade to Db2 11.5/<12.1.3 pureScale
Once topology is aligned, perform a standard Db2 upgrade:
- Upgrade the instance
- Upgrade the database
- Rebind packages
You now have Db2 11.5/<12.1.3 pureScale.
Option B: Upgrade first, then convert
This approach is sometimes preferred when infrastructure for pureScale is not yet available.
- Upgrade 11.1/11.5 non-pureScale → 11.5/<12.1.3 non-pureScale
- Convert 11.5/<12.1.3 non-pureScale → 11.5/<12.1.3 pureScale using backup and restore
Both options are fully supported.
Scenario 2: Db2 11.1 pureScale → Db2 11.5/<12.1.3 non-pureScale
Db2 11.5 pureScale → <Db2 12.1.3 non-pureScale
This is one of the most common upgrade paths, and it cannot be done in a single step. Both the Db2 version and topology change, so the migration must be split into two controlled phases.
Option A: Convert topology first, then upgrade
Step 1 – Convert 11.1/11.5 pureScale → 11.1/11.5 non-pureScale
This step changes topology only. High-level flow:
- Take a backup from the source pureScale system
- Restore it into the target non-pureScale environment
- Run db2CheckSD
- Validate that all members are active
At this point, the database is still Db2 11.1/11.5 but now runs on non-pureScale.
Step 2 – Upgrade to Db2 11.5/<12.1.3 non-pureScale
Once topology is aligned, perform a standard Db2 upgrade:
- Upgrade the instance
- Upgrade the database
- Rebind packages
You now have Db2 11.5/<12.1.3 non-pureScale.
Option B: Upgrade first, then convert
This approach is sometimes preferred when infrastructure for pureScale is not yet available.
- Upgrade 11.1/11.5 pureScale → 11.5/<12.1.3 pureScale
- Convert 11.5/<12.1.3 pureScale → 11.5/<12.1.3 non-n vcpureScale using backup and restore
Both options are fully supported.
What has changed in Db2 12.1.3
Db2 12.1.3 introduced a major and very welcome enhancement. Db2 11.1/11.5 pureScale → Db2 12.1.3 non-pureScale is now supported in a single step
This means you can:
- Take a backup from Db2 11.1 or 11.5 pureScale
- Restore it directly into Db2 12.1.3 non-pureScale
Despite this improvement, Db2 11.1/11.5 non-pureScale → Db2 12.1.3 pureScale is still not supported directly. That means Db2 11.1/11.5 non-pureScale → Db2 12.1.3 pureScale still requires the two-step process described earlier because of conflicted requirements and prerequisites between upgrade and pureScale conversion through restore. Attempting a direct restore will still result in SQL1564N The database is not enabled for the current environment.
Db2 pureScale remains a powerful architecture, but understanding its upgrade and conversion boundaries is essential for successful modernization projects. With Db2 12.1.3, IBM has taken a meaningful step toward simplifying migrations, especially for customers looking to move away from pureScale, while still maintaining architectural integrity.
Further Information and Resources
Read more about the benefits of Db2 pureScale and access further resources.
If you have any questions or comments, or would like help deploying Db2 pureScale, please email Iqbal Goralwalla or get in touch using the contact form. We are always available to discuss how Db2 pureScale conversions can help you provide continuous database availability for your business.
Many thanks to Ryan Xi of the IBM Toronto Lab for his feedback and review of this blog.