Conference smurf::ase

2056.0. "SAP R/3 + Trucluster Available Server" by VAXRIO::LEO () Tue May 13 1997 14:30

    
Hi,

	This is Leo from Digital Brazil.

	I am participating on several SAP bids, down here Brazil.

	Our main competitors are HP and SUN that have entry-level SMP platforms
less expensive than us. 

	I would like to know if I could implement a high available load
distibuted mixed solution, using only two AlphaServer 4100, in order to have
a more competitive approach in terms of price.

	The design of the intended configuration is:


			Digital Unix + Trucluster Available Server
	------------------------------------------------------------------
		|					|
		|  					|
==================================== ==========================================
	AlphaServer 4100 5/466	   | |		AlphaServer 4100 5/466        |
			           | |            	                      |	
		System 1           | |              System 2                  |
				   | |                                        |
 Primary	 Backup		   | | 	Primary			Backup        |
 =======	 =====		   | |	=======			======        |
 DBMS				   | |	Dialog			DBMS          |
				   | |	(70% of all                           |
 Enqueue	 Dialog		   | |	dialog processes)	Enqueue       |
 Update         (70% of all	   | |				Update        |
 Batch		dialog processes)  | |				Batch         |
 Dialog				   | |				Dialog        |
 (30% of all 			   | |				(30% of all   |
 dialog processes)		   | |			     dialog processes)|
==================================== ==========================================
		|				          |
		|   scsi	  _______	scsi	  |
		|________________| DBMS  |________________|
                                 |_______|


The number of simultaneous users will be : 200

Users/Module:

	FI - 50
	MM - 30
	CO - 20
	SD - 50

Questions :
==========

1) Is the configuration shown above possible to be implemented ? Is it 
   conceptually correct ?

2) In case of failure of the System 1, will be the System 2 able to stop the
   R/3 dialog processes, start the DBMS, enqueue,update,batch processes (that
   were running at System 1) and then restart the dialog processes (that will 
   be more than before) in order to support the new workload generated by all 
   users now accessing the System 2 ?

3) In case of failure of the System 2, will be the System 1 able to just start 
   more dialog processes in order to support the users that were being served
   by System 2 ? What happens with the R/3 applications that were being served 
   by the dialog processes on System 2 while the new dialog processes are being 
   "migrated(started)" to System 1 ?

4) Can I say that I have a 3-Tier Client/Server solution before failure and a 
   2-Tier Central System solution after that ?

5) Are the SAP R/3 + Trucluster Available Server scripts ever written to 
   implement these recovery procedures ?



	Any help would be very appreciated.

	Thanks in advance.

	Best regards,

	Leo
	Digital Technical Support

    Hi Leo,
    
    For 150 users I think you could get away with a 4000 (as opposed to a
    4100). Cheaper, and it grow up to be a 4100 one day.
    
    Astra Pharmaceuticals here in Australia have a similar scenario whereby
    the Database Server will fail over to the Application Server. If the
    App Server fails, the users just connect to the Database server (rather
    than failing over). 
    
    They had a system failure at Christmas, and again a month (or two) ago
    and it worked like a charm. All over and done with in a matter of
    minutes.
    
    If you get CSS to stick it all in a rack you have one beautiful
    solution.
    
    cheers,
    
    Stuart 

    Stuart,
    
    	Thank you very much for your very quick answer.
    
    	It will be very useful for me on my future configurations.
    
	Best regards,
    
    	Leo
    	Digital Technical Support
    	Brazil