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Zero Downtime Option (ZDO) of SUM – SAP Upgrade Project Planning

Now that we are in a consumer-driven digital economy era, staying up to date in this digital transformation world is key. To catch up with ongoing digital transformations, SAP continues to deliver the innovations and resolutions, in the form of new products, Enhancement Package, support package stack. For obtaining these innovations SAP system maintenance/upgrade is obligatory and this requires a maintenance window of an SAP system.

However, with increasing business demand, the availability of core SAP systems (SAP ERP, SAP S/4HANA) are indispensable to the organizations to support ongoing business operations. For these organizations, downtime on any day of the year extremely affects the business.

The solution is SAP next-generation Downtime Optimization upgrade approach called “Zero Downtime Option of SUM (ZDO)”.

I am pleased to be part of multiple Light House SAP ZDO projects and PoC’s executed in North America as ZDO architect and SAP upgrade specialist with close collaboration with SAP ZDO product management(Jens Fieger and Team). In this blog, I am going to talk about how to plan ZDO projects or how can you leverage Zero Downtime Option of SUM for your upgrade project based on my previous project exercises/experiences and ZDO cutover runtimes.

Introduction: Zero Downtime Option of SUM (ZDO) of SUM

 

The basic principle of ZDO upgrades is “Upgrade the SAP System while Running Production Operations in Parallel”. During a ZDO upgrade, the system runs productively on the old release and at the same time, the ZDO procedure executes the upgrade procedure. Hence the upgrade can be performed without technical downtime.

 


In this blog, I am not getting into the technical details of “Zero Downtime Option of SUM (ZDO)”. If you want to be more familiar with ZDO, please check the following SAP blog and recordings from SAP TechEd.

  • Replay of SAP TechEd 2019: CAA301 – Leveraging Zero-Downtime Maintenance for SAP S/4HANA
  • Replay of SAP TechEd 2018: CNA306 – Get Your SAP S/4HANA Ready for Running a Zero-Downtime Update Project


Do you need a more detailed understanding?

If you are looking for further information about how ZDO works in detail and would like to be one of the pilot project participants in the next months, feel free to get in touch with Jens Fieger (Product Manager Downtime Minimization of Cloud & Lifecycle Management). Or if you are SAP MAXAttention, SAP’s Premium, and Enterprise Support customer please reach out to your respective Technical Quality Manager (TQM) from SAP.

All prerequisites, as well as a detailed description of the registration process to be a pilot customer, is described in the following SAP Notes:

2707731 – Prerequisites and restrictions of Zero Downtime Option of SUM for SAP S/4HANA.

2163060Prerequisites and restrictions of Zero Downtime Option of SUM for SAP Business Suite


How to plan the ZDO project or how can you leverage Zero Downtime of SUM for your upgrade project?


Step 1: Identify if the respective system qualifies for ZDO

Well, the ZDO of SUM is “available on request” for SAP Business Suite system as per SAP Note 2163060 and available for service-based pilot projects only for SAP S/4HANA as per SAP Note 2707731.

There are no separate license fees for using the ZDO of SUM. Since ZDO of SUM options is not generally available for customers, customers are requested to follow special guided registration processes mention in SAP Notes 2163060 &  2707731 to avail & enable this option in the SUM tool. However, the acceptance of your registration ticket depends on the Minimum source release of your SAP system, project scope, and the availability of the SAP Back Office team. SAP reserves the right to decline registration ticket. If the registration ticket is accepted, then SAP Back Office will provide you with documentation on how to activate the ZDO of SUM and provide support with regular incident processing in case of issues. SAP Back Office team does not take any responsibility for planning the project since it is always under the responsibility of the customer.


Step 2: Understanding of the ZDO

Before beginning it is very very very important!!! to understand how the ZDO works. SAP development has introduced many automated smart solutions inside the ZDO. By using ZDO, the SAP system is handled slightly differently compared to the standard or nZDM update approach. Hence, it is mandatory to understand, how the upgrade works in ZDO. If you are SAP MAXAttention customer, please reach out to your respective Technical Quality Manager (TQM) from SAP to schedule a planning workshop on ZDO.

 

So, what are the critical phases in a ZDO of SUM that you need to know?

Following are some of the critical phases or topics you must know:

  • Building the Bridge instance
  • User rollover to bridge instance
  • What does it mean to your business to be on Bridge Instance?
  • Table classification
  • Impact analysis
  • Ramp down, Bridge Restart, ramp up
  • Testing strategy on Bridge instance
  • Fallback option with ZDO,
  • Restrictions of ZDO enablement

The picture below highlights the critical phases in ZDO of SUM


 

Step 3:  Plan for Proof of Concept (PoC)

Once you have the required approvals from the SAP Back Office team and understanding of ZDO, SAP Backoffice will provide the parameter to enable ZDO and provide access to SAP pilot ZDO note that contains the ZDO guide which enhances the standard SUM guide. The next important step is to execute the Proof of Concept (PoC). PoC is mandatory since it is the key deciding factor that enables and gives clarity on whether you can continue with the project with ZDO of SUM tool or not.

Following are the general feasibility checks that you may have to perform to make sure if the ZDO is an appropriate option for your upgrade maintenance event.

These are the high-level feasible checks that are evaluated as part of PoC since they lay down a path for the beginning of the ZDO project. The PoC will be done in close collaboration between SAP and the customer and the POC System is supposed to be a copy of the Production system!


Step 4: Planning the upgrade project

After the successful evaluation & outcome of ZDO PoC, you can choose to continue the project with ZDO of SUM. Of course, the project must be separately registered with SAP as described already for the PoC. Then Yes! it is the time to plan the project by considering the ZDO boundary conditions.

Following is the high-level example project plan defined the ZDO product management. However, this may not be valid for every SAP customer since every SAP system is different. It is important to plan the project according to your/customer’s in-house environment/ requirements by following SAP best practices. Make sure to perform impact analysis in every cycle.

After getting into the execution of a project you should plan for one of the test cycles as per the following screen. This cycle cannot be far from the production cutover and on the same line, it should not be very close to production cutover.


Step 5: Planning the production cutover

Before beginning the production cutover plan, you should be ready with the following information for the successful Go-Live of Upgrade project with ZDO of SUM.

  • Results of impact analysis and agreement from the respective business teams on read-only tables.
  • User rollover to bridge time
  • Results of critical business process on bridge subsystem (which runs on source release)
  • The runtime of upgrade during the bridge with production load simulation (bridge runtime)
  • List of ramp-down & ramp-up activities
  • Application servers restart by SUM time (only technical downtime)
  • Post activities & validation activities
  • Silent Data Migration runtime
  • Overall business downtime (ramp-down + time for system restart + ramp-up + further post upgrade activities)


Example ZDO cutover

 

It is very important to know when to rollover to bridge instance, how long you are planning to be on the bridge instance, restrictions on the bridge instance, and how much time ZDO takes to complete the upgrade. The timing of all these aspects in the production cutover is very critical for the success of the Go-Live. Any misjudgment can jeopardize Go-Live, as a matter of fact, this can be possible with any project.


Some real-time customer ZDO cutover numbers:


Customer 1:

As per SAP compliance, I cannot name the customer however these numbers are from a project that I am part of.

Scope: This customer executed an EHP upgrade from SAP ERP 6.0 EHP7 SPS 10 to SAP ERP 6.0 EHP8 SPS 13 using Zero Downtime Option of SUM for their ECC System upgrade (database: IBM DB6 11.01, size 22TB).

Outcome:

The cutover time for the system restart was ~20 mins for 30 app servers. (excludes ramp up/down and post-upgrade activities)

Note: These runtimes do not include pre and post activities times. They are execution times without dialog, issue handling, and error resolution time.


Customer 2:

Again, as per SAP compliance, I cannot name the customer however these numbers are from the project that I am part of.

Scope: This customer executed an EHP upgrade from ERP 6.0 EHP7 SP11 to ERP 6.0 EHP8 SP09 using Zero Downtime Option of SUM for their ECC System & HR system upgrade (database: Oracle 12.1.0.2, size 21TB).

Outcome:

The cutover time for the system restart was ~10 mins for ~16 app servers. (excludes ramp up/down and post-upgrade activities)

Note: These runtimes do not include pre and post activities times. They are execution times without dialog, issue handling, and error resolution time.


Customer 3:

Again, as per SAP compliance, I cannot name the customer however these numbers I got from product manager Jens Fieger.

Scope: This customer executed an EHP upgrade from ERP 6.0 EHP7 SPS17 to ERP 6.0 EHP8 SPS13 using Zero Downtime Option of SUM for their ECC System (database: HANA 2.0 SP4, size  14TB).

Outcome: The cutover time for the system restart was ~4 mins. (excludes ramp up/down and post-upgrade activities)

Note: These runtimes do not include pre and post activities times. They are execution times without dialog, issue handling, and error resolution time.

 

For all these customers, the achieved cutover time was less than 20mins. However, business downtime was different since all the customer follows post activities differently.

Many factors influenced SUM runtime for all these customers to vary for example Type of DB, size of DB, H/W resources, etc.

 

Conclusion :

I hope now you understood, what is the difference between regular SAP system upgrade vs SAP system upgrade with ZDO and how much cutover time possible by using ZDO or how much sap system upgrade downtime can be saved.

I hope this blog helps you in planning your next upgrade with ZDO!

 

Thanks to Jens Fieger for helping out in all ZDO projects & PoC’s. Please do visit his SAP TechEd sessions and blogs, they are very informative and helpful.

For more details:

 

Parishudh
Senior Technology Consultant
IT Planning & Maintenance Optimization
Center of Expertise – Customer Success – Intelligent Delivery Group
SAP America Inc.

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