Ressources of proxmox with KVMs

webass

Active Member
May 14, 2015
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Hi,
I woudl like to know in general about setting up the RAM on KVMs and the used ressources...
When I havea 68GB RAM server and I want to have like 20 KVM with Windows in runing...
Isnt it wise to use 500 to 4000 MB dynamically?

If they are fixed like 20 * 2000 it will get very close when I use 20 VMs more and then I will get problems right?

When and how is the ressource of RAM from the real hardware finished? What can I do with wirtualization ...? How virtual is it really?

Right now the server is generally reachable and so... but as soon as 3 people from different locations work and opened consoles like 2 each it starts to not respond anymore...
What has the console to do with it ?

Further a question...
I Installed it this time over debian repositories and when I go through I have a datacenter with a node and only eth0 as network..

When I installed it with the Image over LARA I always ended up with eth0 bridged to vmbr0

We only want to run KVMs but... does this bring a disadvantage to us... ?

Thx upfront...

Andre
 
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About memory:
I would advise againt overcommitting memory ( ie: you should share the amount of RAM you have between your guests and set that to a fixed sized size in the hardware RAM).

You can safely overcommit the cups, if your host hast resl 16 cores, you can assign 2 virtual cores to each VM, up to 40 virtual cores if you have 20 virtual machines. This works very well.

About performance:
If you have that amount of VM on a single host, I hope you have a very fast storage, because this will be for sure a bottleneck.

About installing on top of Debian:
Yes you can manually create the vmbr0 bridge but it is not a hard requirement, it is fine to to do NAT with your VMs for instance.
 
What a great and most comlete answer.
Thanks.

It makes me think and want to know more
...

We use a server with HDD SATA ... just ole stuff from hetzner bidding stock.
Am trying to find the best way to be productive...

So, when we use it. the 16 GB RAM server can open 5 consoles before it breaks down , kinda.
so two of them would result in 10 open consoles at a time

Now in contrary to a 64GB RAM server which can ALSO only open 5 consoles at a time...

What is goin on with the consoles...? Which makes them depend on working open ?

Our goal is, to find the best possible server farm so that as many possible workers can run a KVM on it...

Whats your suggestion. ?

EDIT: We just found that the CPU on the one has no extra high graphics spicifcations. the i7 2600 we also use has HD Graphics on board... So the Consolses are running great...
 
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-the 16 GB RAM server can open 5 consoles before it breaks down , kinda.
so two of them would result in 10 open consoles at a time
Now in contrary to a 64GB RAM server which can ALSO only open 5 consoles at a time...
EDIT: We just found that the CPU on the one has no extra high graphics spicifcations. the i7 2600 we also use has HD Graphics on board... So the Consolses are running great...

what you mean by "open consoles" and "break down"?

the "console" in pve terms is a way for a client web browser to access VMs or CTs.
If you refer to the java/vnc console to pve host or vm or ct, could it be your client pc that can' open more than 5 of them? Or is it the pve server to "break down"?

And what happens (and where, on which host, client or virtualized machine) if you try to open the sixth "console"?

the load on the hypervisor is bound to cpu, ram, network and storage utilization. I think graphics capabilities have a lower weight here.

a bit more of specs about your vm/ct conf, network and storage could help to figure out what happens...

Marco
 
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Hi,
thx for answer.
I will look into the configs... and what else happens ... Get back later.

It is about the NoVNC and then the whlle dashboard is unusable so the pve service...
When I tried to access the server over shell I had not problems.
 

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