Possible to increase real-time factor of VM?

[Engo1]

I am running an application on a VM that generates data.  The application runs at 1 * real-time.  That is, by running for 60 minutes it produces 60 minutes worth of data.

What I hope to achieve is an increase in the real-time factor of the application.  For example if the real-time factor was increased from 1 to 2:  By running for 60 minutes it will produce 120 minutes worth of data.

The application does not have native support for increased real-time factor.  So I was hoping it is possible to use a setting of the VM to increase the speed, analagous to a fast forward button.

If you have any ideas for how to achieve the above, please would you share them here.

I appreciate anyone's time, and thanks in advance for your help with this strange request!

Conrad

[PUREJOY]

If I understand your question correctly, I may have two answers for you.

One obvious and lame method is to over provision the VM with lots of memory, CPU, multiple scsi adapter/NICs, more storage than required and run the VM at 1* , move up to 2* , 3* ... But that's quite too easy (and lame)... lets make it complicated :smileyhappy:

VMware has a new feature of hot add CPU and memory, maybe you should explore that aspect. It needs some scripting and it may not be as simple as you want (like the FF button you mention).

Here is a thought to try out-

1. create a VM which has minimal mem/CPU\

2. Using Thin provisioning create a 2 TB of datastore and add it to the VM (so datastore is taken care off_

3. Using hotadd feature, add more as and when you need to

Now for the caveats,

1. adding is easy but removing is hard. Memory added can't be removed and I haven't seen support for hot-unplug on CPUs in windows. SOme Linux  distros has hot add (memory) and hot plug (CPU) support

2. a lot of guests have issues with dynamic add. (My suggestion is to start off with SMP (atleast 2 vCPU) and add more CPU, its less pain)

3. YOu may have to reboot guest to make sure this works. so you need to select an OS which support Hotadd (Windows 2008 R2 SP1 for ex doesnt' need reboot)

4. Writing the scripts can be challenging as the APIs are there and hard to decipher. Your milage will vary

[mcowger]

Good idea, but adding CPUs wont make the clock run faster in the VM, it will just add processing power.

There's no way to magically increase the clock rate.

[Engo1]

Hi McGower

Yes, you have the right idea of what I want to achieve.  There is no setting within the application to increase the rate (this is what I meant by 'native support') so I was hoping the VM would allow me to do so.

It's a pity that this idea doesn't seem to be possible.  Do you know of any other way to speed up the machine?

[PUREJOY]

There is no other way to "speed up" but to increasing more CPU and other resources needed to "speed up". Its not like a car where you shift the gear and more power would come forth :smileyhappy: There is no such thing in a VM world...

[mcowger]

Thinking outside the box here (and well outside the support guidelines!):

When you have VMware time sync with host enabled, and the host discovers that the VM is behind on time, I believe it rolls forward the time by increasing the tick rate artifically (or at least, it used to back in the 3.5 days).  You could potentially bring up this VM with time sync disabled and set an hour behind the ESXi host's time.  Then, enable time sync and hope that it rolls forward the clock faster than real time.

I have NO idea if this would work, but it could be woeth a shot.

Beyond that, I have no idea :smileysad: