Multiple Dispatchers on one server

[cadams]

I apologise if this has been discussed previously, however, I'm asking again because I can't seem to find a definitive answer.

Back in the day when I was designing multi-tiered BI systems (32bit) we used to install multiple Dispatchers on one server, this was due to the memory limitations of a 32bit environment. My understanding was that each BIBusprocess could only handle 2 processes with a  max of 4Gb in size..

EG.
Server1 & Server2
Gateway components

Server3
CM (Primary)
DI1
DI2

Server4
CM (Standby)
DI3
DI4

Server5
CM(Standby)
DI5
DI6

I'm trying to establish if there is still a benefit from doing this now on a 64bit environment ?


Thanks in advance.

[mcc.chernandez]

If you throw enough hardware at a server you can certainly run multiple dispatcher instances, however, if that server goes down you lost all of them. I try to have more of smaller machines to not be affected too much by one going down. This does increase costs though (OS licensing, physical or virtual resources, etc). Did have an interesting use case for a client who was using a mixed Cognos licensing model - named users and PVU. We used multiple instances on (1) server and used routing rules to comply with their licensing setup

[jbertrand]

Hi mcc,

We are attempting to do exactly what you said you did. That is, multiple dispatchers on one server, and then use routing rules to comply with licensing. Named users should use the full power of the machine, but PVU license based requests need to go via the second dispatcher. But the question is, how did you limit the second dispatcher to a lower PVU count than the full machine?

In our case, the second dispatcher is only going to be used for as an Information Distribution PVU (email out reports) and that's it. It's a 200 PVU license. The full server is around 800.

Thanks.
John.
 

[MFGF]

Hi mcc,

We are attempting to do exactly what you said you did. That is, multiple dispatchers on one server, and then use routing rules to comply with licensing. Named users should use the full power of the machine, but PVU license based requests need to go via the second dispatcher. But the question is, how did you limit the second dispatcher to a lower PVU count than the full machine?

In our case, the second dispatcher is only going to be used for as an Information Distribution PVU (email out reports) and that's it. It's a 200 PVU license. The full server is around 800.

Thanks.
John.

Cognos doesn't work that way. If you install it on a server with 800 PVUs of processor, your license would need to cover the 800 PVUs. You need to install your ID instance (and Content Manager) on a separate server with only 200 PVUs - probably a virtual machine is the way to go.

Incidentally, for Information Distribution PVU based licensing, you need to take account of Content Manager processing as well as ID processing for the PVU calculation. Where is your content manager installed? If it's on the 800 PVU server, you will be breaking your ID PVU restriction, even if the ID part is on a 200 PVU server.

I think you need to go back and discuss this with the vendor you obtained your licenses from. Sounds like you might have been given incorrect information?

Cheers!

MF.

[mcc.chernandez]

I should have clarified - in this project we had multiple dispatcher servers. Named user ones were single dispatcher instances. We had one server for PVU. This one had (2) dispatcher instances in separate server groups

[jbertrand]

Thanks for the info MGMF! I wasn't aware the Content manager service played a role in the PVU calculation, I thought it was just where the dispatcher was housed.

All our servers are virtualised, so I'll get the 800 PVU (which has the content manager) changed to a 200 PVU then split out the remaining 600 PVU to another server just housing a dispatcher. Then only route ID requests to the 200 PVU server. That should do the trick.

Cheers
John.

[sdf]

So we really needs to take in consideration the processor model for any virtualized instance since different processors have different PVUs per core. 

[MFGF]

So we really needs to take in consideration the processor model for any virtualized instance since different processors have different PVUs per core.

Only if you are using a PVU licensing model. If your licenses are named-user licenses you don't need to worry about the rating of your CPU.

If you are using a PVU license model, these two pages may help:

https://www-01.ibm.com/software/passportadvantage/guide_to_identifying_processor_family.html
https://www-01.ibm.com/software/passportadvantage/pvu_licensing_for_customers.html

Cheers!

MF.

[sdf]

Good read!

Thanks!