I've read the article a few days ago and it was interesting. As I upgraded vom 2.6.29 to 2.6.30 (Gentoo) I also saw a dramatic increase disk and filesystem performance. But then I realized that the default mode for ext3 changed to "data=writeback". So I changed that back to "data=ordered" and performance was as it was with 2.6.29. I think ext3 with "data=writeback" in a KVM and KVM started with "if=virtio,cache=none" is a little bit crazy. I don't know if this is the case with current Ubuntu Alpha but it looks like so. Regards, Robert > I would like to call attention to the SQLite performance under KVM in > the current Ubuntu Alpha. > > http://www.phoronix.com/scan.php?page=article&item=linux_2631_kvm&num=3 > > SQLite's benchmark as part of the Phoronix Test Suite is typically IO > limited and is affected by both disk and filesystem performance. > > en comparing SQLite under the host against the guest OS, there is an > der of magnitude _IMPROVEMENT_ in the measured performance of the guest. > > I am expecting that the host is doing synchronous IO operations but > somewhere in the stack the calls are ultimately being made asynchronous > or at the very least batched for writing. > > On the surface, this represents a data integrity issue and I am > interested in the KVM communities thoughts on this behaviour. Is it > expected? Is it acceptable? Is it safe? -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
