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SAP Single Instance Review

I recently carried out a Single instance review for one of my clients and wanted to share my thoughts for further insights/feedback from SDN comunity. As part of my review came out with a list of pros and cons for doing the same. I have listed them as tangible/untangible benefits and risks. Would love to hear back from experts who may have done similar analysis.

Single Instance – Benefits & Risks


Tangible Benefits

·            A single instance provides important benefits, including the reduction of infrastructure complexity and the standardization of processes and data.

·            There is flexibility to add new business units

·            Offers ease of business transactions between legal entities

·            Flexibility to add, merge or divest business units as organization grows and changes ·            Integrated information across legal entities

·            No need to implement ALE transactions between multiple instances to allow business transactions between legal entities. Thus reducing software complexity as well as cost of implementation and maintenance.

·            A reduction of the Total Cost of Ownership, simplification of the IT system architecture, and helps achieve global business process harmonization.

·            No need for numerous interfaces between separate SAP instances, which is a nightmare for standardization and as well as expensive to maintain  

Intangible Benefits

·            Single Instance forces a more disciplined approach to business process which in turn results in more reliable information.

·            Results in greater efficiency and effectiveness in our day-to-day business operations

·            Single instance helps underline “global template” philosophy

·            Multiple SAP instances, whether in different countries, locations, or divisions, are difficult and costly to support.

·            Companies with fairly straightforward business processes without a lot of specialization are good candidates for a single-instance project.

·            A well-designed change control framework and appropriate support tools can help you mitigate risks associated with changes to system configuration and development. 


Tangible Risk

·            There is a risk of total system outage for all business units. This can be mitigated with use of UPS system

·            Reduced application data security because data can be accessed across various company codes

·            A change a control process that is too complex can lead to a loss of business agility

·            New changes to be implemented will require approval from Change manager. This can slow down new business requirements implementation.

·            Bigger user change management effort to upgrade single instance

·          Bigger risk (more users affected) each time you upgrade

Intangible Risk

·            Centralized single system places a much higher importance on having the appropriate change control processes in place.

·            Transaction response time from overseas sites

·            Time zone conflict of system resources (example Europe overnight batch transactions during US day time transactions)

.         The transition from multiple instances to a single instance is a complex process.

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  • …is your backup and restore procedure. If you have a multi-integrated environment. You can’t simply restore a system in isolation as you will run the risk of being “out-of-sync” with other systems.
    Restoring a single instance will ensure that, for example your FI and HR data are consistent…
    • Thanks Chris for your feedback. You raised a very valid benefit based on your Basis administration background. Appreciate your thoughts on this.
  • We are on a single global instance of our core system, and we did a landscape consolidation prior to our ECC 6.0 upgrade. I agree that there can be benefits, but I see it as a tradeoff. When you have very different product/ service lines  in very different localities using the same system, it is likely that their processes will vary, sometimes a little, sometimes a lot, presenting challenges to configuration and process design.

    Also in such cases, there may not be standardization in the job roles, which can translate into security challenges. You may have to choose between each unit having their own security roles for their own processes ( = more roles to maintain), or building one-size-sits-all roles granting access to many transactions that are not applicable depending on your business unit, or possibly even some of both approaches for different process areas. It can also present extra challenges when there are many interface jobs that have to be run during “off peak time”, where the windows of quiet time on the system are few and small.

    Those considering such a landscape would do well to consider all the factors. If it is being considered for cost savings, the choice might be better framed as “pay now or pay later.”

    Thanks for raising this topic!

    • Thanks Gretchen for your feedback. I liked your word “Tradeoff” to explain the risks of using Single Instance.
      I have also covered some of this under my Risks section. But I will surely need to consider the security challenge around the single instance.

      thanks again for sharing your thoughts.