What is data archiving?

Data archiving and system decommissioning are often searched for interchangeably, but they solve different problems. Here’s what each one is, how they differ, and how to work out which your legacy systems need.

Data can be categorised in a variety of different ways. Hot, warm and cold data describe how often information is used and how fast you need to access it.

Hot Data – used constantly e.g. active user profiles, real time transactions.

Warm Data – Data you still need, but access less often than hot.

Cold Data – historical data that you rarely look at, but must be accessible and kept for legal or compliance reasons.

This is one way of the many ways to consider how you treat it.

Data archiving is the practice of moving inactive or infrequently used data out of a live application and into a separate long-term archive store, where it remains accessible for compliance, audit and historical reporting. The key characteristic: the original system keeps running. Users still reach the archived data through the live application – for example a SAP user running Information Lifecycle Management (ILM), views archived records inside SAP even though they may physically sit elsewhere. This is why it is sometimes called live archiving. Organisations may archive their warm and cold data in a live archive if the system is still their main system of record and live.

Archiving is well established, and for systems with a long future ahead of them it is often the right housekeeping: it keeps databases lean, performance sharp and storage costs down. Data archiving software exists precisely for this job, and in the SAP world it is a mature discipline with its own file format (ADK) and decades of accumulated archive files.

System decommissioning goes a step further: it retires the application entirely. The system is switched off, its licences, infrastructure and support contracts end, and its data – structured and unstructured, including any archive files – moves to a completely separate platform where it stays searchable, reportable and compliant. Nothing is left running.

When a legacy ERP system is being closed down and replaced, the hot data will be transferred to the new system. Organisations may consider using live archiving in the new system for warm data. They are likely to decommission the cold data and also consider whether any of the warm data is also decommissioned.

Data from multiple systems can be held in a decommissioned store. Organisations typically build a store over time containing data from a variety of systems.

SAP data archiving is the most searched version of this question, and the place the two ideas most often blur. Many organisations have archived SAP data for years – ADK files quietly accumulating alongside ECC. But with SAP ECC reaching end of life and estates moving to S/4HANA, the question changes. Archiving assumed the system would stay; now the system itself is going.

At that point an SAP archiving solution no longer answers the problem if a greenfield migration is performed, because there will be no live SAP system to view the archive through. The historical data – database tables and archive files alike – needs a new, independent home before the old system is switched off. That is system decommissioning, and it is a different discipline with different tooling regardless of which vendors systems are used.

• Will the application still be running in three years? If yes, archiving keeps it as lean as possible. If no – or if you wish the answer were no – you need a decommissioning plan, not an archive.
• Is the data the only reason the system is still on? Then you are paying full legacy running costs for what is effectively read-only history. Decommissioning keeps the history and drops the cost.
• How many systems are you keeping alive for their data? Legacy data archiving system by system multiplies stores and access routes. A decommissioning platform holds data from many retired systems – SAP and non-SAP – in one searchable place.

Cella is not data archiving software – deliberately. Cella is a legacy system decommissioning platform: it extracts everything from a system that is being retired, including existing SAP archive files, holds it in one secure, reportable store, and lets you switch the old system off while keeping every record accessible and compliant. If your systems have a future, consider archiving them. If they don’t, see the systems Cella decommissions – SAP, Oracle, PeopleSoft, JD Edwards, Infor, mainframe and more – or start with why decommissioning cuts legacy costs.