Archiving SAP ECC After S/4HANA Migration: Strategies for Long-Term Access and Compliance

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A couple of weeks ago, I wrote a blog on the importance of archiving in the S/4HANA world, with a particular focus on the role of data archiving in preparing for a Brownfield conversion. That article explored why managing historical data is not simply a best practice, but often a prerequisite for a successful system conversion. For those interested, you can find it here.

However, many organisations will opt for Greenfield or Selective Data Transition (SDT) approaches when moving to SAP S/4HANA. These methods, while enabling a clean start or targeted data migration, invariably leave behind substantial volumes of historical data in the legacy SAP ECC system. This data may include customer orders, financial transactions, materials movement records, and HR data—much of which remains critical for legal retention, audit trails, or occasional business reference.

The challenge here is clear: how does an organisation retain and provide access to this historical ECC data without continuing to operate a full SAP ECC environment, with all the cost and operational overhead that entails?

This blog explores three practical strategies I have worked with to address this specific challenge. Each approach offers a different balance of cost, complexity, and access to data. I will examine the benefits and limitations of: continuing to run the ECC system in a low-cost cloud setup; using SAP’s own ILM Retention Warehouse; and employing a third-party archiving solution such as SNP’s Data Fridge. The aim is not to prescribe a single solution, but to help organisations make informed decisions based on their compliance requirements, IT landscape, and long-term data strategy.

Once an organisation has successfully migrated to SAP S/4HANA using a Greenfield or Selective Data Transition approach, the legacy ECC system often contains a vast amount of historical data that has not been transferred to the new landscape. While the operational system may no longer require this data for day-to-day processing, it remains highly relevant from both a compliance and business perspective. Therefore, the need to create a reliable, accessible, and cost-effective archive becomes a priority rather than an afterthought.

From a regulatory standpoint, both New Zealand and Australia impose clear obligations around the retention of financial and operational records. In Australia, the Corporations Act 2001 mandates that companies retain financial records for at least seven years after the transactions covered by those records are completed. This includes not only accounting documents, but also supporting evidence such as invoices, receipts, and audit trails.

Similarly, in New Zealand, the Companies Act 1993 requires that accounting records be kept for a minimum of seven years, a timeframe that aligns closely with Australian requirements and is enforced by the Inland Revenue Department (IRD) for tax purposes.

Privacy and data protection regulations also play a significant role in shaping retention strategies. Under the Australian Privacy Act 1988 and the New Zealand Privacy Act 2020, organisations are required to store personal information securely and only for as long as it is necessary to fulfil the original purpose for which it was collected. However, this is often balanced against legal or operational imperatives to retain data for extended periods, particularly where it may be relevant for dispute resolution, compliance investigations, or audits.

Multinational organisations operating in this region must also consider international standards and frameworks, or industry-specific obligations in sectors like financial services and healthcare. These layers of compliance contribute to a complex regulatory environment where reliable access to historical data is not just advisable—it is essential.

Beyond compliance, business operations frequently depend on access to historical information. It is not uncommon for customer service teams to require visibility into orders placed years earlier, or for finance departments to revisit old postings during audits or reconciliations. Equally, materials or product teams may need to reference historic manufacturing or quality data that is no longer held within the active S/4HANA environment. In such cases, the inability to retrieve legacy data quickly can lead to operational bottlenecks, reputational damage, or even legal exposure.

There is also a compelling IT rationale for formally archiving the ECC system. Maintaining an entire SAP ECC environment simply to support sporadic access to historical data can be costly and inefficient. It consumes infrastructure, licences, and skilled resources that would be better deployed elsewhere. Moreover, legacy systems that are no longer patched or monitored effectively present an increasing security risk over time. By consolidating and decommissioning old systems in a controlled and compliant manner, organisations can reduce their total cost of ownership while improving their overall IT security posture.

For these reasons—compliance, operational continuity, and IT optimisation—creating a permanent and accessible archive of the SAP ECC system should be considered a critical part of any S/4HANA transition programme.

For some organisations, the most straightforward way to preserve access to legacy SAP ECC data post-migration is to continue operating the ECC system itself, albeit in a streamlined and cost-optimised form. Rather than decommissioning the system entirely or attempting to extract and rehost data elsewhere, this approach involves moving the ECC environment to a hyperscaler such as AWS, Microsoft Azure, or Google Cloud Platform. Once hosted in the cloud, the system can be downsized, placed on scheduled or on-demand availability, restricted to a limited number of users, and configured with reduced infrastructure to lower ongoing operational costs.

The main advantage of this approach lies in its simplicity. Because the data remains within the original system, there is no need for extraction, conversion, or transformation processes. Users retain full access to transaction history, reports, and custom developments exactly as they existed prior to the S/4HANA migration. This can be particularly important in cases where the data model is highly customised or where the organisation lacks the time or appetite for additional data projects following the transition. Moreover, the user experience remains familiar, with access via SAP GUI or existing interfaces, which helps to minimise training requirements and change management effort.

However, there are several trade-offs to consider. Continuing to run ECC in any form still requires SAP licensing coverage and incurs infrastructure charges, even when scaled down. The environment must be maintained on an ongoing basis, including operating system patching, backup management, and general technical support. This may be difficult to justify when access to the data is only occasional. There is also the longer-term risk associated with skills attrition, as fewer consultants and internal teams maintain expertise in ECC and NetWeaver technologies in a post-S/4HANA landscape.

An additional consideration is that users will typically need to access data across two separate systems—S/4HANA for current operations and ECC for legacy reference—introducing process inefficiencies and potential confusion. In cases where the historical ECC system contains personal data, organisations must also have a clear strategy to meet obligations under privacy legislation such as the Australian Privacy Act or New Zealand's Privacy Act. This includes the ability to comply with data subject rights, including the right to erasure (or “right to be forgotten”), which can be technically challenging to implement in a legacy environment not designed with such controls in mind.

I implemented this approach for a customer in the UK who had made the strategic decision to move away from SAP altogether. Their requirement was to retain the ECC system for ten years to meet regulatory and audit requirements, but without the burden of managing it internally. We migrated the system to AWS, using the opportunity to modernise the operating system and database versions to ensure greater supportability over the long term.  We used “Schedule Pixie” to manage the availability timetable of the system and limit the EC2 running cost to the customer.  Further into the contract when access requirement became much more sporadic, we switched to user initiated access allowing the system to be shutdown most of the time.  While we recognised that access to newer SAP kernel versions was not available, which eventually limits the ability to patch components of the system, the customer deemed this an acceptable risk.

This model is best suited to organisations with complex historical data requirements that must remain untouched for legal or operational reasons. It offers full data fidelity with minimal disruption, provided the long-term cost, dual-access implications, and compliance obligations are understood and accepted.

Another approach for archiving legacy SAP ECC data following a migration to S/4HANA is to leverage SAP’s own Information Lifecycle Management Retention Warehouse. This solution is specifically designed to support the decommissioning of legacy SAP systems, enabling organisations to extract and store data in a purpose-built, lightweight system that provides read-only access to historical records. Unlike running a full ECC system, Retention Warehouse is not intended for transactional use, but rather to serve as a compliant archive that aligns with long-term retention policies.

SAP ILM Retention Warehouse operates by first identifying and extracting relevant data objects from the source ECC system, based on configured retention rules. These rules are defined within SAP ILM and are aligned to regulatory or organisational requirements—for example, retaining payroll records for seven years or customer data for a defined statutory period. The extracted data is then transferred into a dedicated system, which can be either a reduced SAP NetWeaver stack or embedded into another ILM-enabled landscape.

The key advantage of this method is that it is fully SAP-supported and purpose-built for compliance. It allows organisations to define and enforce legal retention periods while eliminating the need to keep an entire ECC environment operational. Furthermore, the solution can act as a central repository for data from multiple decommissioned SAP systems, which is particularly useful in larger enterprises with complex system landscapes or history of mergers and acquisitions.

Typical ILM Retention Warehouse Scenario

That said, Retention Warehouse is not a plug-and-play solution. It requires upfront investment in licensing and technical setup, as well as expertise in ILM configuration, data object modelling, and extraction processes. In practice, this often means engaging with SAP or specialised consulting partners who understand the intricacies of both ILM and the legacy ECC data structures. Even once the system is running, viewing and navigating archived data may require additional support or custom developments, particularly when dealing with bespoke or industry-specific data objects.

In my experience, this approach tends to work best for organisations that already have ILM capabilities in place and understand how to operate within its framework and are not concerned about maintaining a familiar user experience for accessing legacy data

Overall, SAP ILM Retention Warehouse offers a robust, compliant solution for organisations with sophisticated data governance needs. It is particularly suitable for those with existing ILM investments or where long-term access to ECC data must be tightly controlled and demonstrably compliant with regulatory requirements. However, it demands a strong internal capability or trusted partners to deliver successfully.

A third option available to organisations looking to preserve access to their legacy SAP ECC data is to adopt a third-party archive solution. These platforms are designed specifically to extract and compress legacy ERP data—often from both SAP and non-SAP systems—and rehost it in a lean, purpose-built environment optimised for long-term retention and occasional access. One such example is SNP’s Kyano Datafridge, which has gained traction in recent years for its ability to offer a simple yet powerful user experience, without the operational burden of running a full SAP ECC stack.

Third-party tools such as Datafridge are generally faster to implement than SAP ILM Retention Warehouse and involve less setup complexity. In many cases, the vendor provides preconfigured logic for handling key data objects, standard UI components, and compliance features, removing the need for extensive internal configuration or development. Because the ECC system itself is no longer needed once data is extracted, customers are able to eliminate infrastructure and SAP licensing costs associated with maintaining the source system. In addition, some of these platforms allow organisations to bring together data from multiple systems—both SAP and non-SAP—into a single searchable archive, which can be a major advantage for businesses with diverse landscapes or legacy M&A history.

That said, third-party platforms do introduce a level of vendor dependency. Once data is moved into a proprietary archive system, switching to another solution later may not be straightforward. Although licensing and operational costs are generally lower than running an ECC system, they still need to be evaluated carefully—particularly in the context of long-term retention timelines. Moreover, organisations should conduct due diligence to ensure that the solution meets the required regulatory and audit standards, particularly around access controls, audit trails, and data privacy obligations.

I recently proposed SNP Kyano Datafridge to a customer in Europe that had already invested in some SAP ILM licences. Despite this, we concluded that the Fridge solution offered a better overall fit for their needs. One of the deciding factors was its ability to embed directly into the customer’s existing S/4HANA environment, allowing users to access legacy and current data from a single interface. The user experience is deliberately familiar: standard SAP-like transactions, a data browser similar to SE16, and the ability to generate reports that could join current S/4HANA data with archived ECC data. This eliminated the need for additional training or tools, which significantly accelerated adoption. Furthermore, the platform supported data lifecycle rules and retention policies, helping the customer meet its compliance requirements in a transparent and auditable way.

An example of Financial Accounting documents in transaction FB03 in SNP Kyano Datafridge

This approach is particularly well suited to organisations that are focused on speed, usability, and cost-effectiveness, and who may not have the in-house resources or ILM maturity required to implement a native SAP solution. It provides a clean break from legacy infrastructure while still preserving the data in a structured and accessible form. However, like any strategic platform decision, it should be approached with a clear understanding of long-term support, data governance, and interoperability with the wider SAP landscape.

Selecting the most appropriate strategy for archiving legacy SAP ECC data is not a one-size-fits-all decision. It requires careful alignment with the organisation’s broader compliance obligations, technical capabilities, and operational goals. In practice, several key factors tend to shape the decision-making process.

Compliance and legal requirements are often the starting point. Organisations operating in regulated industries—such as utilities, financial services, or pharmaceuticals—typically face stricter data retention obligations, which may extend beyond standard accounting or privacy legislation. For example, in both Australia and New Zealand, financial records must be retained for at least seven years, and certain industries may impose even longer retention periods. The solution selected must therefore provide not only data availability but also a demonstrable means of managing data lifecycle rules, access controls, and audit trails in line with regulatory expectations.

The expected frequency and nature of data access is another significant consideration. Some businesses require regular or ad hoc access to historic transactional data, particularly for customer service, dispute resolution, or comparative reporting. In such cases, a solution that offers familiar user interfaces and integrated reporting tools may be more appropriate. Conversely, if access is only needed for the occasional audit or compliance check, a more lightweight or read-only archive may suffice. The balance between usability and cost efficiency must be evaluated through the lens of real business need.

Budget constraints naturally influence the selection. While continuing to run an ECC system provides full access with minimal functional change, it is rarely the most cost-effective long-term approach. SAP ILM Retention Warehouse, while robust and aligned with SAP’s roadmap, requires licensing and expertise that may not be readily available. Third-party solutions can offer a good compromise in terms of lower total cost of ownership and faster time to value, though they still involve commercial and vendor considerations that must be carefully reviewed over the archive’s intended lifespan.

The availability of internal IT skills is also a major driver. Supporting a legacy ECC system over many years may require specialised SAP Basis, ABAP, and infrastructure skills that are becoming less common in organisations focused on cloud-first and S/4HANA strategies. By contrast, options like ILM or third-party archives reduce technical dependency, but may still require knowledge of data structures, compliance tools, or integration approaches to operate effectively and securely.

Finally, timing plays a practical role. In many projects, the S/4HANA migration is under tight deadlines, leaving limited bandwidth to design and implement a fully-fledged archive solution in parallel. In such cases, an interim solution—such as continuing to host ECC temporarily in the cloud—can buy time while a more strategic archive approach is developed post-migration. However, this must be done with a clear understanding of the costs, risks, and potential lock-in associated with delaying the final archiving decision.

Ultimately, the most suitable path is the one that strikes the right balance between risk, cost, compliance, and usability, within the specific context of the organisation’s future SAP landscape and operational needs. It is a strategic decision that should be made with the same level of rigour as the S/4HANA migration itself.

Creating a permanent archive of SAP ECC data following a Greenfield or Selective Data Transition to S/4HANA can be an essential requirement. Historical data remains deeply intertwined with compliance obligations, operational continuity, and the ability to respond effectively to regulatory or audit enquiries long after the legacy system has ceased to be operationally relevant. However, the path to achieving this does not need to be prohibitively complex or expensive.

As this blog has explored, organisations have more than one viable option. Maintaining ECC in a scaled-down cloud environment offers the simplest and most complete access to historical data, but it comes with ongoing costs and maintenance effort. SAP ILM Retention Warehouse provides a native, policy-driven solution well suited to organisations with mature ILM capabilities and a strong focus on compliance. Meanwhile, third-party tools such as SNP Kyano Datafridge offer a pragmatic alternative for those looking to balance ease of implementation with a familiar user experience and lower operational footprint.

The right choice ultimately hinges on a mix of regulatory needs, business priorities, internal skillsets, and budgetary constraints. What works well for a multinational in a tightly regulated industry may not be appropriate for a leaner business looking to minimise IT overhead. In every case, the decision should be made deliberately and with foresight, ideally as part of the broader S/4HANA transformation roadmap rather than as an afterthought.

Handled correctly, the archival of ECC data can be transformed from a burden into a strategic asset—one that supports legal defensibility, operational agility, and reduced technical debt. As more organisations embrace the future with S/4HANA, ensuring that the past remains accessible, compliant, and well-governed is a mark of a truly sustainable SAP landscape.