Arch Linux

synthead

Member

Registered: 2006-05-09

Posts: 1,344

4-core server running multiple headless VirtualBox instances: slow?

Like title, I have a VM server that hosts about 15-ish VMs, and when about ~5 of them are running and I do something major on one of them (like compile software), the server gets excruciatingly slow.  The SSH console even takes ~15s to respond to keyboard input, for example.  How can I fix this?  Shouldn't the kernel's scheduler manage the individual processes of the VMs and prevent this?

graysky

Wiki Maintainer

From: :wq

Registered: 2008-12-01

Posts: 10,732

Website

Re: 4-core server running multiple headless VirtualBox instances: slow?

Is it too simplistic to think that the ratio you're using, 4:1 (virtual:physical) is simply too rich given the cost of running the virtualization itself requires some overhead?  Do you grind to a slow pace is you're running say 4 VMs and load up one?  If so, where is the choke point?  6? 7? Etc.

Last edited by graysky (2012-10-03 21:20:52)

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ngoonee

Forum Fellow

From: Between Thailand and Singapore

Registered: 2009-03-17

Posts: 7,362

Re: 4-core server running multiple headless VirtualBox instances: slow?

How much RAM is allocated to each VM? If (for example) you have 4GB of RAM (you probably have more) and you start running each with 800+ MB of RAM, you'd hit swap REALLY quickly.

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