![]() ![]() Once done, restart the SAP system and start the ASCS and the ERS with appropriate startsap commands. Step 9 : Add the below parameter on the Default profile The first example shows two SAP SIDs, both with ERS1 architecture where: SAP SID1 is deployed on shared disk, with ERS1. Figure 1: Configuring the Enqueue Server in an HA Environment All clients and the replication server too are connected to the standalone enqueue server. A mix of ERS1 and ERS2 is not supported in the same cluster. The replication enqueue server runs on another host and contains a replica of the lock table (replication table). Step 8 : Add the below parameter on the ASCS instance profile Both Enqueue replication server 1 (ERS1) and Enqueue replication server 2 (ERS2) are supported in multi-SID configuration. Another great high availability feature was the enqueue replication server, which made the enqueue server breakdown-proof. An application server instance connects directly to the Enqueue. Classical Central Instance or Standalone Enqueue. You have installed the (A)SCS instance as described in Installing the Standalone Enqueue Server. Step 7 : Create an instance profile in the profile directory* The Enqueue Server is a standalone component and does not require access to the database. The ABAP+Java Configuration comprises the installation of: Central Services Instance for ABAP (ASCS Instance) Enqueue Replication Server Instance (ERS. If you want to make your system a high availability solution, you need the enqueue replication server as well as the standalone enqueue server. Step 6 : Create a start profile in the profile directory* Step 5 : create a ers.lst file with the below contents and place in the exe directory created in step 2Įnrepserver|ensmon|enqt|libsapu16_mt.so|libsapu16.so|libicuuc30.a|libicudata30.a|libicui18n30.a|librfcum.so|sapcpe|sapstartsrv|sapstart|sapcontrol|servicehttp|ers.lst Related Content Introduction The standalone enqueue server (SAP Central Services SCS) is used in NetWeaver Web AS Java to provide a locking service based on the enqueue function. Commands to check status of ERS/SCS instances 5. Sapmc.jar|sapmc.html|frog.jar|soapclient.jar Checking the Installation (Replication Server) 4. ![]() There is only one enqueue server in a distributed SAP system. Step 4 : Copy the following to the sapmc directory created in Step 2 The enqueue server (also known as the lock server) is the SAP system component that manages the lock table. Sapcpe|sapstart|sapstartsrv|sapcontrol|enqt|enrepserver|ensmon|libicudata30.a|libicui18n30.a|libicuuc30.a|libsapu16_mt.so|libsapu16.so Enqueue Replication Server keeps a replica of lock table in the shared memory of the passive node and in case of failover all lock entries can be retrieved and the consistency of the system is ensured even in case of Enqueue Server restart. Step3 : Copy the following to the exe directory created in step 2 Step2: create the following directory structure under the file-system where you will install ERS Step1: Log on to your host where u need ERS and switch to adm user ![]() The SID (SAP system ID) of the system is called PLL in the graphic.Enqueue Replication Server Part 2 - Installing ERS The enqueue server is installed on two physical hosts ( host1 and host2, which have the same virtual host name ( hahost). When the replication server is running it is supplied only with delta information arising from each request to the enqueue server. It retrieves the replication table from the standalone enqueue server when it restarts. If the replication server fails, it can be restarted on a different host. The HA software also ensures that while the standalone enqueue server is out of action, clients' connection attempts go through host B instead of host A. The replication table stored on the replication server is transferred to the standalone enqueue server and the new lock table is created from it. Whilst SAP Central Services and DBMS layer are also deployed across two zones, only one will be active at any point in time. The same is true for the DBMS layer, which will be deployed across the same zones as SAP Central Service. If the standalone enqueue server fails, it is started by the HA software on the host on which the replication server is running. The SAP Central Services instance that uses enqueue replication will be deployed between two zones.
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