Creating SAP system clones using Solaris 10 virtualization concepts (Part 2)
Creating SAP system clones using Solaris 10 virtualization concepts (Part 3)
Creating SAP system clones using Solaris 10 virtualization concepts (Part 4)
As of today in many productive system landscapes there are still long planned downtime caused by updates, patches and similar tasks. Introducing new techniques and concepts like the Solaris shadow system approach can help to minimize the effects of this downtime.
In the use case described the effective downtime of the productive system is just a second and therefore not recognized by most of the clients. During the upgrade process the productive system is available in read-only mode. Of course this does not reach every requirement for system availability – but it can help to minimize the effects of planned downtime dramatically.
The concepts described here is quite simple and easy to setup. For the show case, build in features of Solaris 10 were used and no additional hardware or software products were required. When automating the functionalities in a reusable manner, an update can be applied easily and without deeper knowledge of the environment.
The use case described is based on Sun Solaris 10. Of course it cannot be applied 1:1 within different environments.
However, the principles described are representing a general concept and are not related with any specific platform or product. The basic idea is to provide a shadow system which can be updated independently from the productive system and become the new productive system by switching the roles afterwards.
Combining the clone technology with SAPs System Copy also a change of the platform and database is possible. For example after creating a shadow system a system copy could be made based the shadow system. Afterwards this shadow system could be installed on a different host using the same configurations and switched with the productive system later.
However, due to the diversity of system landscapes each setup of a shadow system has to be considered very carefully.
With the upcoming generations of operating systems and hardware architectures new features like ZFS and virtualization will become a standard functionality in many system landscapes.
Large application platforms like SAP NetWeaver can benefit from this trend using these techniques effectively.
For products like the SAP Enterprise Portal a synchronizing mechanism is in preparation. This functionality will allow the creation of a setup described here without any read-only phase: After cloning and updating the system the data changed in the old system during that timeframe can be synchronized with the new system.
An abstract about the general principles is available at SDN’s SAP NetWeaver How-To Guides section How To Minimize Effects of Planned Downtime.