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seen Nov 3 '13 at 18:49

Ruby on Rails coder, redeemed from PHP hell some years ago.


Sep
24
awarded  Autobiographer
Sep
7
comment Ubutu/KVM: High iowait on guest nodes, root node fine
Then I'd expect similar iowait on the root node, and I'd expect to see a lot of disk activity. But there is (almost) no disk activity at the time of the test. I guess I'll keep looking.
Sep
6
comment Ubutu/KVM: High iowait on guest nodes, root node fine
Looks like I spoke too soon, simply editing the fstab to refer to vda instead of sda was enough. So my target device is now working: <target dev='vda' bus='virtio'/> Unfortunately it doesn't appear to have made a great deal of difference to the iowait issue.
Sep
6
comment Ubutu/KVM: High iowait on guest nodes, root node fine
Thanks for your answer, this sounds like the likely culprit. Unfortunately changing only this stops the guest booting. It seems to require adding the virtio_pci driver to the guest's init ramdisk and reconfiguring Grub/fstab, which I haven't quite figured out. I will update when I've had a chance to experiment.
Sep
5
comment Ubutu/KVM: High iowait on guest nodes, root node fine
I tried the various caching and io settings mentioned in that article, as mentioned in my question. I've read the linked IBM docs but they didn't have any recommendations beyond these settings as far as I could tell. But perhaps there is more tuning to be done?
Sep
5
asked Ubutu/KVM: High iowait on guest nodes, root node fine
May
5
awarded  Student