Load balancing

[Former Member]

Hi All,

Can anyone please explain to me how load balancing is done. We have a CI and an application server. We want to distribute the user load between these two servers.

I know about logon groups (smlg). But i heard that load balancing can be done by making changes to the .ini files of saplogon on the users desktops. I am confused as to what is the right approach. I am sure it is pretty straight forward, but i want to do it correctly. Please suggest.

Also, whar it transaction rz12 used for?

Thanks in advance

Cyrus

[Former Member · Accepted solution]

Great, thanks for the info.

Now, I want to use a logon group. We have created 2 logon groups in our PROD system and assigned different application servers.

What changes do i have to make to my saplogon.ini file to use the load balancing feature and I also hear that I have to make an entry in the /etc/services file. Where do i do that and what entries are needed to use it?

Thanks again

Cyrus

[Former Member · Accepted solution]

Hi Cyrus,

on the client side you have to add the message server ports to the services file (c:/windows/system32/drivers/etc/services)

for example:

sapmsXXX 3600/tcp

sapmsXYZ 3601/tcp

XXX is the SID of the instance, 00 and 01 are the coresponding system numbers.

In saplogon, you can do all in the GUI, you don't have to edit the ini files.

go to groups, enter SID and message server and you should get the names of the logon groups below.

Regards,

Pascal

[Former Member]

HI

GOOD

SAP Load Balancing

The benefit of segregating user groups by line-of-business (using logon groups) is related to the point that groups of users (like SD users or HR users, for example) tend to use the same sets of data. They (generally) work with the same groups of tables and hit the same indexes using the same programs (transactions).

So, if you can group all of the users hitting the same tables, onto (or one set of) App server(s), then you can tune the App server buffers to a much greater extent. If the FI users (generally) never hit against the HR tables then the App servers in the FI group don't (generally) have to buffer any HR data. That leaves you free to make memory and buffer adjustments to a more drastic extent, because you don't have to worry (as much) about screwing the HR users (as an example), when you're adjusting the FI server group.

So, (in opinion only) you should start with a buffer hit ratio analysis / DB table & index access analysis (by user group) to see where you would get the best benefit from this kind of setup. If you don't have this kind of info, then creating logon groups by line-of-business may have no benefit (or worst case, may make performance degrade for the group with the highest load %). You need some historical information to base your decision on, for how to best split the users up.

You may find that 50% of the load is from the SD users and so you may need one group for them (with 3 App servers in it) and one other group for everyone else (with the other 3).

The logon group(s) will have to be referenced by SAP GUI, so SAP GUI (or saplogon.ini + maybe the services file, only) will have to change to accomodate any new groups you create in SMLG. Also consider that there's variables for time-of-day (load varies by time-of-day) and op-mode switches (resources vary by op-mode).

GO THROUGH THIS LINK

http://help.sap.com/saphelp_nw04/helpdata/en/b5/e8239ef7bd494f896a84625d4b688f/content.htm

THANKS

MRUTYUN

[Former Member]

Hi Cyrus,

you just have to define the logon groups in SMLG and to enter the name of the logon group also in the saplogon for each user. RZ12 is only for RFC, so this is not relevant for load balancing of users.

Regards,

Pascal