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nZDM Java Part 1: Prepare the Physical Host of your Target System

The solution near-Zero Downtime Maintenance for SAP NetWeaver Java enables maintenance activities in SAP NetWeaver Java-stack systems with almost no downtime. It is designed to accelerate and simplify any updates in your Java-only system, while your users barely notice the improvements you’re doing “under the hood”.

In a series of several blogs, we’ll show you a practically applicable example of a nZDM Java procedure.

In order to have a smooth and trouble-free process, though, preparation is key. In our particular situation, the proper preparation of the physical host of your target system is the goal you have to achieve first. We’ll show you an example for you to follow and perform yourself, so that you can do the process without special help.

Prerequisites

The following steps should be performed first:

  1. Start the recording in your production SAP NetWeaver Java-stack system (hereafter referred to as “source system”).
  2. In the nZDM Java GUI dialog Specify Source System Database Host, you enter the IP address of the source system database host (it must be accessible from the target system).
  3. You copy/clone your source system, then perform the maintenance activities in the copied system (also referred to as “target system”). Use any procedure and tool of your preference to make the system duplicate, for example one of the following SAP products:

You can also use VMWare to copy and isolate the target host. See VMWare Lab Manager Online Library.

While the cloning process takes place, production operation continues in the source system, which is still running on the original release.

Example for preparing a physical host

Now we’ll describe an example you can follow along, where you copy the system using SWPM on physical hosts.

1. Preparing the Target System Host

Start with an empty host with the same OS as your source system host.

  1. Login to your target system host as user root.
  2. Depending on oyur operating system, edit the file /etc/hosts (Linux) or C:\Windows\System32\drivers\etc\hosts (Windows). In the file, add the IP address of the target system host and the hostname of the source system host as a first line in this file, for example:
<IP address of the target system> <hostname of the source system>. fqdns <hostname of the source system >

You can see the IP address of the target system host by running ifconfig (Linux) or ipconfig (Windows).

For SUN OS: As you enter the virtual hostname in the /etc/hosts file, you need to also create the network interface related to that host with ifconfig, for example

ifconfig net0 addif Linux <IP_address_of_the_VH>/32 up

For Windows OS: Execute Step 7 in SAP Note 1564275.

2. Configuring the Isolation of the Target System

Configuring the target system isolation is crucial for the successful execution of the nZDM Java procedure. You have to isolate the target system from the production network to avoid interference with the source system. This can be done by means of an appropriately configured firewall, or by means of adequate network interface configurations (for example, subnetting). You can use iptables commands to perform on Linux machines.

For additional information, see nZDM Guide: nZDM Java Guides – <guide for your system> – section Configuring the Isolation of the Target System.

After you prepared the target system host, create the target system as described in the blog post specific to your database:

You can also see our blog post nZDM Java: minimize the business downtime of your SAP Process Orchestration maintenance activity.

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