On Wed, Jan 21, 2009 at 01:34:48PM -0500, Dustin Henning wrote:
I tried the Qumranet drivers before I went with Xen. I don't think there is necessarily a problem with the Qumranet drivers, in fact, they could potentially have better inbound speeds than the GPLPV ones (though it seems unlikely as much as people test and James works on them on the xen-users list). The reason the Qumranet drivers don't cut it is because they are only network drivers. This means your data access (and possibly other stuff GPLPV hits) is still fully virtualized. Another reason I went with Xen is the PHY: option. I use a physical data source, as opposed to a file, for my guests. Each one has its own HD, actually, though partitions or RAID arrays would obviously work as well. If I remember correctly, when I tried this (some time ago), KVM had no such option.
KVM / QEMU don't make any artificial distinction between block devices and files, like Xen did. You can use any block device, lvm volume or file with QEMU / KVM - should be parity with Xen here.
Network driver is by far the most important one to virtualize since it suffers much worse degradation when emulated, which is why PV net for Windows was done as a priority. SCSI in QEMU should offer pretty good performance - significantly better than IDE, and much closer to PV disk.
Daniel
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