DAM Update Asset Workflow generates oversized sub-assets from large PDF files
When using Adobe Experience Manager (AEM) 6.5 Managed Services, uploading large multi-page PDFs can lead to unexpected repository growth. The DAM Update Asset Workflow’s Create Sub Asset step splits each page into a separate sub-asset. For some PDFs, each sub-asset is nearly as large as the original file, resulting in massive storage consumption.
To fix this, optimize the PDF before upload using Adobe Acrobat Pro or use the Print to PDF workaround to reduce resource payload.
Description description
Environment
- Product: Adobe Experience Manager (AEM) 6.5 Managed Services (Long-Term Support)
- Feature: DAM Update Asset Workflow, (Create Sub Asset step)
- Constraint: No out-of-the-box font/resource optimization during sub-asset creation
Issue / Symptoms
- Uploading a large PDF (for example, 50 MB, 900+ pages) to AEM results in the generation of hundreds or thousands of sub-asset PDFs, one for each page.
- Each sub-asset (per-page PDF) is almost as large as the original file. Example: 900 sub-assets from a 50 MB PDF result in over 40 GB total consumption.
- The issue is PDF-dependent: Some PDFs do not exhibit this; the issue is dependent on how the PDF was originally created (resource, font embedding).
Cause
- Many publishing/print workflows generate PDFs that embed all fonts and images for fidelity.
- When AEM’s Create Sub Asset step extracts individual pages, it replicates all embedded resources for each sub-asset, even those only used in part.
- AEM 6.5 does NOT automatically optimize or subset fonts/resources during this process.
- Result: Each per-page PDF sub-asset inherits the full payload, causing excessive storage growth.
Immediate Consideration
If generating sub-assets (per-page PDFs) is not a business requirement for your use case, consider disabling or limiting the Create Sub Asset step in your DAM Update Asset Workflow. Disabling or restricting this step can prevent excessive storage usage and workflow overhead. You can configure the number of sub-assets generated via the step properties—for example, setting to zero or a small value, or removing the step entirely for PDFs. See theAEM 6.5 documentation on managing sub-assets for further configuration options.
Resolution resolution
Follow these steps:
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Confirm that the DAM Update Asset Workflow includes the default Create Sub Asset step for processing PDFs.
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Optimize the original PDF before uploading to AEM:
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Using Adobe Acrobat Pro:
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Open the PDF in Acrobat Pro.
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Go to File
>Save As Other>Optimized PDF. -
In the optimization dialog:
- Enable font subsetting (Subset embedded fonts).
- Enable image compression.
- Choose deduplication of shared objects/resources.
- Review other advanced options as appropriate.
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Save the optimized PDF.
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Test by uploading the optimized PDF to AEM; check that sub-assets are now much smaller.
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If Acrobat Pro optimization doesn’t reduce sub-asset size, use Print to PDF:
- Open the PDF file.
- Go to File
>Print. - Select Adobe PDF as the printer.
- Under Page Sizing & Handling, choose Custom Scale and enter a value less than 100% (for example, 90%).
- Print and save the resulting PDF. This flattens resources and can reduce file size, though some layout fidelity may be affected.
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If neither approach resolves the issue and full page-level sub-assets are required:
- Consult with the Adobe Acrobat support team for advanced resource/font optimization or troubleshooting.
Related reading
- Manage compound assets with references and multiple pages in AEM 6.5 LTS User Guide.
- Process assets using workflows in AEM 6.5 LTS User Guide.