[SOLVED] Hyper-Threading vs No Hyper-Threading; Fixed vs Variable Memory

[Carlos Estrada]

Hi. I have a question for Proxmox 4.4.

There is the option "Ballooning" which is available with the option "Use fixed size memory". In the help manual says :

Even when using a fixed memory size, the ballooning device gets added to the VM, because it delivers useful information such as how much memory the guest really uses. In general, you should leave ballooning enabled, but if you want to disable it (e.g. for debugging purposes), simply uncheck Ballooning.

I'm configuring a Windows server 2012 VM. I want to have a fixed size memmory, but I'm confused about this option. Should I enable it?

 

[sdet00]

This Wiki Article suggests that the Ballooning driver is a source of performance problems.

https://pve.proxmox.com/wiki/Performance_Tweaks

Is this still the case on Proxmox 7?

 

[Ray_]

This Wiki Article suggests that the Ballooning driver is a source of performance problems.

https://pve.proxmox.com/wiki/Performance_Tweaks

Is this still the case on Proxmox 7?

I have the ballooning driver active on all 15 Windows VMs and I didn't notice any performance issues.
This wiki entry is from the 4th of August 2015‎ (6,5 years).

 

[sdet00]

Yup, it links here so I figured an update can't hurt.

 

[CTCcloud]

So it appears no one has said anything about this so I'll make a comment. If more people can back this up, even better.
I turned off memory ballooning on all VMs on our weakest node. After doing so, those VMs had performance like what they'd have on the stronger nodes. This may seem anecdotal but I used the recommendation and came up with better performance. It certainly would seem that the recommendations from 2014 are still valid.

 

[sdet00]

So it appears no one has said anything about this so I'll make a comment. If more people can back this up, even better.
I turned off memory ballooning on all VMs on our weakest node. After doing so, those VMs had performance like what they'd have on the stronger nodes. This may seem anecdotal but I used the recommendation and came up with better performance. It certainly would seem that the recommendations from 2014 are still valid.

Interesting findings. Do you have more information on how the performance was improved? What % difference are we talking?

 

[CTCcloud]

Honestly, I know everyone always wants to see some sort of metric but without context, that would be no better than standard anecdotal evidence. I've now taken all of our KVM VMs off of ballooning and they are all noticeably faster. I know this is anecdotal and perceptual but believe you me, that matters greatly to our customers and therefore to us. We use RDP to sign in through the cloud to all these servers and the sign in is now twice as fast as it was. As far as metrics, I'd say the ones originally posted to this thread years ago would probably still be valid from the performance increase I'm feeling.

 

[CTCcloud]

Perhaps some helpful numbers ..
We have a Dell Server with dual 18 core processors that normally runs at a CPU load of 18 to 22 at this time of the morning (8:40am EST) and right now is only running at 14
We have a couple of other Dell servers with dual 12 core processors that usually run at about 12 to 14 on CPU load at this time of the morning that right now are only running 5 and 7
Significant return of CPU power back to the hardware and nothing else changed except getting rid of the ballooning