Disadvantages of running TM1 through a VM in Production

[ExApplix]

Hi,

I want to know what are the disadvantages of running TM1 (and EV) through VM (VMWare) in Production enviornment. I think there may be some performance issues (RAM or Processor).

Is this a recomended practice and is supported by IBM/Cognos?

Please post your recomendation/suggestions ASAP.

Thanks

[lotsaram]

by no means exhaustive ...

Advantages:
- minimise overall hardware
- keeps IT folks happy as virtualisation is flavour of the month/decade

Disadvantages:
- performance hit, rule of thumb is around 20% (as all requests effectively have to go through 2 operating systems)
- additional configuration
- potential performance and stability hits if RAM and CPU configuration is not good for in memory apps
- TM1 database size limitations as VM software seldom supports server instances of > 8 Gb RAM

[LoadzaGrunt]

- potential performance and stability hits if RAM and CPU configuration is not good for in memory apps

On that point, you might want to ask specifically about the amount of RAM guaranteed to your VM that is running TM1. Some VM 'controller' programs that are running several VMs on one physical machine are configured to 'hot-swap' RAM resource between the various VMs depending on actual demand. This means that one minute your TM1 model is running fine but come month-end when the RAM demand hikes up you are suddenly finding the performance has died because your RAM allocation was given to another VM during your mid-month 'downtime' and suddenly you've hit the page file.

My 2c is that VMs are good for small models that are maybe not much more than PoC or development instances.