best practices for kvm setup?

[Rik Theys <Rik.Theys@esat.kuleuven.be>]

Hi,

I'm looking into virtualizing some of our servers onto two (or more) 
physical nodes with either KVM or Xen. What are the 'best practices' for 
running virtual _servers_ with KVM? Any good/bad experiences with 
running KVM for virtual servers that have to run for months on end?

I've installed ubuntu 8.04 because it should have KVM as the default 
virtualization tool and is the only 'enterprise' distribution with kvm 
right now. I used one host to act as an iSCSI target and installed 
ubuntu with KVM on two other nodes. I can create a virtual server with 
virt-manager, but it seems live migration is not (yet) supported by 
libvirt/virsh? So how are other people running their KVM virtual 
servers? Do you create a script for each virtual server and invoke kvm 
directly? How do you do the live migration then? Launch the script with 
an 'incoming' parameter on the target host, and run the migrate command 
manually? Or is there an other (automated) way? I once tried the live 
migration on a test host and if I recall correctly, the kvm process kept 
on running on the source host even after the server was migrated to the 
target? Is that the expected behaviour?

What type of shared storage is best used with KVM (or Xen for that 
matter)? Our physical servers will be connected to a SAN. Should I 
create volumes on my san and export them to my physical servers where I 
can then use them as /dev/by-id/xxx disk in my KVM configs? Of should I 
configure my two servers into a GFS cluster and use files as backend for 
my KVM virtual machines? What are you using as shared storage?

Regards,

Rik


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