Of all the seven Rs of migration strategies, ‘retain’ is one of the two so-called passive responses. Unlike refactoring, replatforming, rehosting, relocating and repurchasing, retaining, as the name suggests, means a decision has been made to not migrate an application to the cloud.

It should be noted, however, that this may well take the form of a pause or ‘point-in-time’ strategy, meaning the strategy is to not migrate for the time being, but the decision will be reassessed at a later point.

Despite the many advantages of being in the cloud, there are some circumstances where it may not be a useful strategy or the best business decision.

Reasons to retain an application on-premises or in-house can include:

  • It is due for retirement shortly and the business has made an executive decision to ride out its depreciation value to get the maximum financial benefit from the application.
  • It will require a significant amount of re-architecting before it is suitable for migration.
  • The cost of migration is prohibitive or exceeds allocated budgets.
  • Any disruption a migration program may entail is not practical at the given time.
  • It is a legacy operating system or application that is not supported by a cloud environment.
  • There are real-time latency requirements.
  • There is a ‘if it ain’t broke don’t fix it’ consideration – an application may be operating so satisfactorily there is no business case to support the cost and disruption of a migration.
  • The organisation or industry must adhere to strict compliance regulations requiring it to keep its data on-premises.
  • The application requires such high performance it is better suited to remaining on-premises.

It should be stressed, however, that none of the above may be set in stone. The circumstances may evolve and the reasons for retaining an application may change with them. For this reason, it’s important to qualify a decision to ‘retain’ with another ‘R’ – revisit. It’s necessary to revisit the application usage every six months to reappraise the situation. The decision to retain may be a time sensitive one, that there are other factors preventing the migration or there is a lack of important information. When that new information becomes available, a different strategy may be a better option. For instance, companies abiding by compliance regulations may find that the compliance landscape has changed, or those constrained by latency requirements could see technical developments that now make migration to the cloud possible.

The hybrid approach

Migration to the cloud does not have to be an all or nothing affair. It’s likely that organisations will look to retain portions of their IT portfolio because they are more comfortable having these applications on-premises and under their control. In such cases, they can implement a hybrid or part migration strategy. This is a considered approach for those in industries that are regulated or bound by constitutional rules that require them to store and/or run aspects of their business and services on-premises or even within specific regions.