We have installed SAP NW 7.1 CE in MSCS for High Availabilty. Our primary application server is installed in a separate server. I can only access SAP via the hostname of the primary application server (i.e. http://<hostname of primary appserver>:5<instance#>00/nwa) and not via the virtual hostname of the MSCS cluster. Is there any configuration I have missed? I have followed all the preparation needed for HA installation.
What do you mean by Virtual Hostname ? Message Server ? If yes, then Yes, you should be able to access nwa from your message server. try as http://<messageserver>:5<nr>00/nwa.
The Other Option is you can install WebDispatcher to loadbalance the CE and access the application thru common url. You can use SAPINST to install SAP WebDispatcher.
The message server can run on either node since SCS is installed in MSCS cluster. This is the reason I assume I can access SAP via the virtual hostname of the cluster. I tried to access SAP via the local hostname of the current active node but I can't still access SAP. I can only access SAP via the hostname of the primary application server.
Ok. I got what you are talking about. Node A and B has virtual node names and you install application using Virtual names and failover virtual hostnames instead of physical, Is this your concept ?
If yes, then you need to check your default profiles, environment variables and change all those values pointing to Virtual hostname instead of Physical and try again.
I have worked on this in UNIX and never tried in Windows..lets try . MMC is showing physical or Virual hostnames ?
Regards,
Arjun
Edited by: Arjun Venkateswarlu. on Feb 2, 2012 3:35 AM
Yes, Node A and Node B has a virtual host name. We installed the application using its physical hostname. What I can see from MMC is SCS instance in virtual hostname, ERS in physical hostname of Node A and Node B and Primary Application Server in physical hostname where PAS is installed. We have separate server for our PAS.
You have your Primary Appl. Server in a different server so this is the only way to access, the Central services are in Cluster but you cannot access them directly.
If I can only access SAP through the primary application hostname then what will happen if I install additional application server to my existing installation? Since SAP is installed in High Availability (MSCS), then this will allow me to access SAP via the virtual hostname wherever nodes SCS is running. Do you have additional thoughts on this?
As already posted, you only has SCS in HA, the "normal" way will be that you has one CI and as many DI as you need and use a Web Dispatcher. If CI fails then WD will send the requests to remaining DI´s so you won´t loose service.
In MSCS if you install as per the guide, Instances are not HA because they are installed locally in each node, if you have two nodes then you install CI in Node A and DI in Node B, if Node A fails then SCS resources migrates to Node B, CI is out and you work with the DI installed in Node B.
To be able to use any of the Intances installed you need a Web Dispatcher that does the load balancing between the CI and DI´s, if CI fails then you get service from the DI´s.
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