Advantages and Disadvantages of 3-tier structure

[Kavya]

Hello,

We have a Cognos 10.2.1 instance in 3-tire structure.
We have 2 Linus VM's as web servers and 3 Linux VM's as application servers.

We are planning to install Cognos analytics on new VM's. So trying to understand the advantages and disadvantages of following the same 3-tier structure with Cognos Analytics.
Want to see if we can have both Web servers and application on same VM's. Will that cause any issues?

Any suggestions/advices will be helpful.

Thanks.

[MFGF]

Hello,

We have a Cognos 10.2.1 instance in 3-tire structure.
We have 2 Linus VM's as web servers and 3 Linux VM's as application servers.

We are planning to install Cognos analytics on new VM's. So trying to understand the advantages and disadvantages of following the same 3-tier structure with Cognos Analytics.
Want to see if we can have both Web servers and application on same VM's. Will that cause any issues?

Any suggestions/advices will be helpful.

Thanks.

Hi,

It's often the case that an organization has a separate web server tier simply because they already use dedicated web server machines or VMs, and it made sense to utilize these rather than having that functionality duplicated on the application servers. It also means that if a specific application server goes offline or is swamped with requests, the gateway / web server isn't affected as it is running on a separate server. Often you will find setups with a single web server/gateway, multiple application servers, and a content manager (maybe with a second standby). In this situation, if you wanted to run the gateway/web server within the same VM as the application servers, you would end up with multiple web servers with different URLs, or else you'd pick just one application server to host the web server, and run the risk of it being unavailable if that one server had an issue.

The other consideration is whether you will need to continue to use a web server or if the inbuilt servlet gateway would suffice - in which case you could do away with the web server tier. Reasons you need a web server with Cognos these days are for single signon, and for webdav image browsing. If you're not doing either of these you may not need one.

Cheers!

MF.

[Kavya]

Thank You MF for the reply.

Pardon my little knowledge on this.

Could you please explain more about this below statement:
if you wanted to run the gateway/web server within the same VM as the application servers, you would end up with multiple web servers with different URLs, or else you'd pick just one application server to host the web server, and run the risk of it being unavailable if that one server had an issue.

Can't we do the load balancing with just the application servers? I did not understand the point of having different URLs.
Yes, we currently do load balancing URL with 2 gateway VM's on 10.2.1 which are separate from application servers. So is this not possible to do just with Application servers ? That is what I am understanding here?

Thanks.