running in a virtual environment

I'm wondering what experience people have had running pg 8.x in a virtualized environment. Are there any best practices to follow that differen when running on a real metal? Are there performance issue? What virtual environment seems most friendly to pg ? Xen, VMWare, other? What about storage; is it best to keep the cluster in a filesystem that is part of the vm-image or on a mounted file system that exists external to the image? (in other words, a /dev/sdxx that is really some NAS type of device, or NFS? CIFS?)

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David Bear
College of Public Programs at ASU
602-494-0424