Config for full Load balancing (web + apps)

[maxa]

Hi all,

I have some doubt about the configuration of the load balancing for the application servers (BI tools).
Cognos version: 10.2.2
Can someone help me on this?

I already read a lot on the IBM website and this interesting previous topic (http://www.cognoise.com/index.php/topic,24202.msg76586.html#msg76586).

my architecture is the following (full Win 2012 R2):
Load balancer F5 for my 3 web servers configured in ISAPI.
1- gateway + IIS
2- gateway + IIS
3- gateway + IIS

also a Load balancer F5 for my 3 Apps servers:
4- cognos BI apps + CM master
5- cognos BI apps + CM slave
6- cognos BI apps + CM slave
all these 3 servers are configured with option "cluster compatible".

7- MS SQL for the CS and Audit DB.
unfortunately, budget too tight to have failed over on this critical part ((
but I have the DR in case of real crash to switch on.

I also have the following configuration:
1- dispatcher URI for gateway: 1, 2, 3
2- dispatcher URI for gateway: 2, 3, 1
3- dispatcher URI for gateway: 3, 2, 1
4- content manager URI: 1, 2, 3
5- content manager URI: 1, 2, 3
6- content manager URI: 1, 2, 3

Hope this configuration will also help a lot of people to initiate their platform as it s a summarise of my expertise and information I could found here and there.

So my questions are:
The load balancing for the web servers (1, 2, 3) is done with the option "cluster compatible", right?
But what I have to do to configure the load balancing on cognos for the application servers (4, 5, 6)? Do I have to configure the load balancer IP on the "controller URI for gateway" on server 1, 2, 3 and/or "external dispatcher URI" on severs 4, 5, 6?

Thank you in advance for your help.

[sunosoft]

I am not that much expert to comment on external load balancing.

However as far as I know...you need external load balancer(F5), for cognos gateway servers

And you can use the build in load balancing functionality for Cognos application servers. Instead of going with cluster compatible option you can go with weighted round robin option in application server and you would not require external load balancer here.

[maxa]

Yes, we use external LB F5 for web and apps.

unfortunately I can t use internal LB as our Infra department required external LB for web AND for apps.
I never setup LB for apps till now. only for web which is the easy part.

[MFGF]

Hi all,

I have some doubt about the configuration of the load balancing for the application servers (BI tools).
Cognos version: 10.2.2
Can someone help me on this?

I already read a lot on the IBM website and this interesting previous topic (http://www.cognoise.com/index.php/topic,24202.msg76586.html#msg76586).

my architecture is the following (full Win 2012 R2):
Load balancer F5 for my 3 web servers configured in ISAPI.
1- gateway + IIS
2- gateway + IIS
3- gateway + IIS

also a Load balancer F5 for my 3 Apps servers:
4- cognos BI apps + CM master
5- cognos BI apps + CM slave
6- cognos BI apps + CM slave
all these 3 servers are configured with option "cluster compatible".

7- MS SQL for the CS and Audit DB.
unfortunately, budget too tight to have failed over on this critical part ((
but I have the DR in case of real crash to switch on.

I also have the following configuration:
1- dispatcher URI for gateway: 1, 2, 3
2- dispatcher URI for gateway: 2, 3, 1
3- dispatcher URI for gateway: 3, 2, 1
4- content manager URI: 1, 2, 3
5- content manager URI: 1, 2, 3
6- content manager URI: 1, 2, 3

Hope this configuration will also help a lot of people to initiate their platform as it s a summarise of my expertise and information I could found here and there.

So my questions are:
The load balancing for the web servers (1, 2, 3) is done with the option "cluster compatible", right?
But what I have to do to configure the load balancing on cognos for the application servers (4, 5, 6)? Do I have to configure the load balancer IP on the "controller URI for gateway" on server 1, 2, 3 and/or "external dispatcher URI" on severs 4, 5, 6?

Thank you in advance for your help.

Hi,

The load balancing for the web servers (1, 2, 3) is done with the option "cluster compatible", right?

Web servers in your case are IIS, and you are using your Load Balancer F5 to load balance requests across all three of them. "Cluster compatible" is a setting that is relevant to the Cognos Application Server processing tier, not to a web server (you define it as a property of a dispatcher, and the Cognos gateway component has no dispatcher of its own). From the spec you posted above, the only Cognos component on servers 1, 2 and 3 is the gateway, and there is no inbuilt Cognos load balancing for gateways. You are using the correct approach in utilising an external load balancer to distribute requests across your three IIS web servers.

But what I have to do to configure the load balancing on cognos for the application servers (4, 5, 6)? Do I have to configure the load balancer IP on the "controller URI for gateway" on server 1, 2, 3 and/or "external dispatcher URI" on severs 4, 5, 6?

Servers 4, 5 and 6 are your Application Server processing machines. You indicated that you have utilised another Load Balancer F5 for these. Can you share how you defined this - are the gateways on the three IIS servers configured to send requests to this external load balancer? How did you set this up?
By default, the three Application Server machines will know about each other and will load balance between each other without use of any external load balancers. Each Application Server has a dispatcher which is registered within the running content manager process. As requests come in from a gateway they are sent to a specific dispatcher, which then load balances between its own connections and the other Application Server dispatchers it knows about in the architecture. To do this, it uses a "Weighted Round Robin" algorithm - which means you can allocate different weights to the dispatchers and in doing so increase or decrease the share of requests being handled by each dispatcher.
Imagine a simple setup where you have one gateway and three application servers - each with the same weighting defined. The gateway will always send requests to the first dispatcher in it's list (defined in the gateway configuration). This dispatcher then has the job of load balancing the requests across the three known dispatchers in the architecture (itself and two others). In low-traffic situations, where less than half of that initial dispatcher's connections are in use, it will handle all requests itself, and not bother to distribute them - there would be no point. Where half or more of the first dispatcher's connections are in use, it will then send requests to the other dispatchers as well as allocating them to its own connections.
If you were to set the load balancing property of this first dispatcher to "Cluster compatible" rather than the default of "Weighted round robin", you would turn off the load balancing. The dispatcher would send all incoming requests to its own connections and not divert them to other dispatchers.

In your case, where you have three gateways behind a Load Balancer F5, each sending requests to second Load Balancer F5 which distributes them to the Application Servers, you'd probably want each of the three Application Server dispatchers to be set to "Cluster compatible". This would mean the load balancing between the servers was done entirely externally by the second Load Balancer F5, and Cognos wouldn't try to "interfere" and add further load-balancing between the dispatchers. Alternatively (as sunosoft pointed out), you could remove the second Load Balancer F5, have the gateways send requests each to a different Application Server dispatcher by default, and have the load balancing set to Weighted Round Robin for each, so they load balance between themselves where necessary.

Cheers!

MF.

[maxa]

thank you MFGF, your comments are always complete and well details.

Thank you for the "Cluster compatible" clarification => it s for the Apps servers and not for the gateway.

In your case, where you have three gateways behind a Load Balancer F5, each sending requests to second Load Balancer F5 which distributes them to the Application Servers, you'd probably want each of the three Application Server dispatchers to be set to "Cluster compatible". This would mean the load balancing between the servers was done entirely externally by the second Load Balancer F5, and Cognos wouldn't try to "interfere" and add further load-balancing between the dispatchers

This is exactly what I need to do. So my first step changing the parameter to "Cluster compatible" looks to be the right thing.
But which values I have to change in cognos configuration to tell it what is the IP of my 2nd LB instead of the dispatchers? is it on the web server or only on the apps servers?

[MFGF]

thank you MFGF, your comments are always complete and well details.

Thank you for the "Cluster compatible" clarification => it s for the Apps servers and not for the gateway.
This is exactly what I need to do. So my first step changing the parameter to "Cluster compatible" looks to be the right thing.
But which values I have to change in cognos configuration to tell it what is the IP of my 2nd LB instead of the dispatchers? is it on the web server or only on the apps servers?

Hi,

I think all you need to know is right here in this helpful technote:

http://www-01.ibm.com/support/docview.wss?uid=swg21341010

Cheers!

MF.

[maxa]

really helpful answer MFGF.

to summarise, the configuration has to be:
on servers 1, 2, 3: Dispatcher URIs for gateway - should have a single reference pointing to the report server's (dispatcher's) load balancer
on servers 4, 5, 6: Gateway URI - this should point to the load balancer for the web servers