PVE 2.3 - help on understanding the memory usage and CPU/core usage

[Nachtfalke]

Hi,

I am using Proxmox VE 2.3 since some weeks - more or less for testing. I do not have much experience with Virtualization just played a little bit with VMware Workstation.

My system is a quad core xeon processor with 2.13GHz and 4GB RAM and 72GB SAS HDD RAID1.
I installed PVE without problems on this HDD. After that I added another 500GB HD SATA RAID1 and installed two VMs on this machine.

My questions are:

• What requierments has the PVE host system ? The wiki is telling something about 1GB or 8GB+. Is this dependent on how much VMs are running on the system ? Is thee some "math" which says that the PVE needs 1GB RAM per VM to manage the virtualization? And how many cores ? I know that the memory and CPU usage of the VMs is dependent on the usage but this is something I can calculate but I don't know what I need for PVE itself.
• I installed the ballooning drivers - if I set the available RAM for a VM between 512MB and 3GB will this automatically increase the RAM on the VM or will this only allow me (admin) to manually increase RAM with some commands without shutting down the VM ? Further can you explain me what the number of "slices" does - when should this be increased?
• I am running on VM with Windows 7 x64 and one VM with Ubuntu 12.10 x64. I can see that KSM is in use. From the wiki I read that this works only when using the same OS on different VMs. Seems like I understood this wrong

I am sure this are really basic questions for people who are using PVE for a long time. For me it would be helpful to get some basics from you

I really appreciate your help!
Thanks in advance!

 

[Nachtfalke]

Hi,

seems like this are stupid questions for you experts but I personally do not have an answer till now.
Perhaps you can give me some short answers.

Thank you!

 

[snowman66]

My questions are:

• What requierments has the PVE host system ? The wiki is telling something about 1GB or 8GB+. Is this dependent on how much VMs are running on the system ? Is thee some "math" which says that the PVE needs 1GB RAM per VM to manage the virtualization? And how many cores ? I know that the memory and CPU usage of the VMs is dependent on the usage but this is something I can calculate but I don't know what I need for PVE itself.

1GB RAM is ok for testing. I would suggest at least 4GB or more RAM. See this document for more information (Best practices for KVM): http://pic.dhe.ibm.com/infocenter/lnxinfo/v3r0m0/topic/liaat/liaatbestpractices_pdf.pdf

am running on VM with Windows 7 x64 and one VM with Ubuntu 12.10 x64. I can see that KSM is in use. From the wiki I read that this works only when using the same OS on different VMs. Seems like I understood this wrong

It's more effective when the VM's are the same.

 

[Nachtfalke]

Thank you very much!

This looks intersting. I will read the articles.