SLD and LMDB Topology: Replacing the Source SLD for the LMDB

Switching the Source SLD of an LMDB

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It is recommended to use just one System Landscape Directory (SLD) system as the source of CIM model, CR Content, and Technical Systems’ data for the Landscape Management Database (LMDB) – see figure 1:

Figure 1: Recommended SLD/LMDB Topology in a default landscape, with the source SLD in the PRD area.

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However, the necessity may arise to change the SLD system you use as the source SLD for the LMDB – usually the central SLD in your landscape, getting the Data Supplier data. The switch may be necessary because you restructure the SLD Topology: How-To Gather and Distribute SLD-Data in Your IT-Landscape?, replace the central SLD with a completely new one, etc.

Here are the points to consider in case of a switch to another SLD and some hints how to prepare the switch. Data retrieved from the SLD by Demo: The Full Automatic Sync Feature in the SLD of SAP NetWeaver 7.1 is an important part of the LMDB content and the basis for all other data. Also, it is forbidden to have the same data retrieved from more than one SLD system, because this will lead to a violation of the unique-path-principle. Therefore, the switch of the source SLD by replacing the central SLD system needs to be planned thoroughly to avoid inconsistencies and gaps in the availability of SLD data.

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Prerequisites

In any scenario, where you want to switch to a new source SLD, the following is needed:

1. Decide on the new source SLD.
   Install a new SLD or prepare an existing one. If you newly install the SLD, using the most recent version is recommended. At least an SLD based on SAP NetWeaver 7.11 should be used.
2. Prepare the new source SLD.
   Import the CIM model; the CR Content version of the current source SLD will be synced into the new SLD by the full automatic synchronization.Note: During the phase when both SLD systems are used, do not update CIM model and CR Content. In case an update is needed, do so in the preparation phase or after the LMDB Source SLD switch is done.

Switch Procedure for the Replacement of the Central SLD

Figure 2: Synchronization between current and new source SLD by bidirectional sync. One Data Supplier is already pointing to the new source SLD:

1. Make the content of the current source SLD available in the new one. 

   – Preferably, create and activate a bidirectional Full Automatic Synchronization connection. (This is done to distribute Data Supplier data during the phase when both SLD systems get Data Supplier data.)
   All available data will be synched into the new source SLD, while the new Source SLD is prepared but not yet acting as a source SLD for the LMDB.Note: Depending on the amount of data in SLD and LMDB, the first phase of synchronization (full synchronization) will take several hours

   – You can also use manual backup and import – also prepare the CR Content in this case. In that case, additionally create bridge forwarding from the new source SLD to the current, to keep Data Supplier data up-to-date until the actual switch

2. Prepare the Data Suppliers of the Technical Systems.
   Re-configure the SLD Data Suppliers of all Technical Systems to point to the new source SLD.Note: If you are using a virtual IP address – or a virtual host name – as recommended to address the current source SLD, no action is required on the Technical Systems. (Remember, one prerequisite is that both SLD systems are using the same port or gateway – for further details, read How to Ensure that SLD Data is Available during Maintenance.)
   One more hint: You can also switch to the virtual address over time, while keeping the real and the virtual address of the initial SLD until all connections are pointing to the virtual address.
3. Prepare the Bridge Forwarding of the new central SLD to all other SLD systems:
   Setup Bridge forwarding to supply all Data Supplier data delivered by the technical systems to all SLD system in landscape areas DEV and QA.
4. In the SAP Solution Manager hosting the LMDB, reconfigure the LMDB Synchronization Connection to the SLD
   (Note that preconditions for that are that data in both SLDs is the same at this point – with no pending changes -, especially CR content and technical system descriptions, as described above):
   In transaction SOLMAN_SETUP go to System Preparation -> Prepare Landscape ->  Setup LMDB (see figure 3):

   Figure 3: Deleting and adding synchronization connection between SLD and LMDB in Setup LMDB.

   – In the edit mode delete the old synchronization connection.

   – Then add the new connection to the new source SLD.

5. After the switch, the old SLD can be shut down or be running in a new role.

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Other Switch Scenarios

Switch Procedure to a Back-Up SLD (in full-synchronization with the central SLD)

This is quite simple. All the prerequisites are fulfilled already, changes in Data Suppliers or forwarding of Data Supplier data is taken care of already, so you only need to follow step 4 in the “Switch Procedure for the Replacement of the Central SLD”.

Switch Procedure to another SLD already Available in the Landscape but not the Central SLD

This is generally not recommended. Some exceptions of this rule may exist. In any case, the prerequisites must be fulfilled.

Occurrence and Handling of Sync Conflicts Regarding the SLD Data Supplier Time Stamp

If you do not use the full, automatic sync for the SLD contents during the change, sync conflict concerning the SLD Data Supplier time stamps will occur. Steps and correction to handle sync-conflicts related to time stamps of SAP Data Suppliers are described in SAP Note 1949792 – Report to resynchronize technical systems and data supplier timestamps from SLD to LMDB.

Additional Information

• SLD Overview @ the SDN: System Landscape Directory
• LMDB Overview @ the SDN: http://help.sap.com/landscape-description -> Landscape Management Database (LMDB)