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I've got several Ubuntu 10.04 virtual machines running as Hyper-V guests on Windows Server 2008 R2 SP1 and they're all perfectly fine.

Today I installed my first Ubuntu 11.10 virtual machine and I'm seeing rediculous pings:

enter image description here

These servers are all connected via gigabit to a local LAN, with almost no network traffic at all1, with a legacy network adapter in Hyper-V.

I'm a bit of an Ubuntu n00b so I don't really know where to go from here. Any ideas?

free -m reports:

             total       used       free     shared    buffers     cached
Mem:           485        470         15          0         63        299
-/+ buffers/cache:        107        378
Swap:          507         20        487

This is within a few mb of our other Ubuntu servers that are on 10.04.

I removed the Legacy NIC and installed a Synthetic one in Hyper-V and this did improve the numbers, in that they're around 10-30ms now, but I would still be expecting <1ms response times.

1As a comparison, I have another Ubuntu 10.04 guest on Hyper-V almost 1,000km away that has a ping of 33ms

Mark Henderson
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  • Have you verified that pings to the physical machine are not being lost as well, to ensure networking issues aren't present, or tried pinging directly from the host machine to one of the virtual machines? – Conspicuous Compiler Nov 20 '11 at 22:54
  • @ConspicuousCompiler - yep, pings to the physical host are correct (`<1ms`) – Mark Henderson Nov 20 '11 at 22:57
  • What does `free -m` on the virtual system report? – Conspicuous Compiler Nov 21 '11 at 00:00
  • @ConspicuousCompiler - updated question – Mark Henderson Nov 21 '11 at 00:04
  • Updated the latest 11.10 kernel? Any differences in integration components between your 10.04 builds and 11.10? – Yolo Perdiem Nov 21 '11 at 00:24
  • @Mark Well, it doesn't look like you're facing heavy swapping, which was my first guess. – Conspicuous Compiler Nov 21 '11 at 00:26
  • @evilensky - Yeah, did an update just after the installation. As for components, it acted in that way right after a standard blank install with no components selected. They're being used as a really, really light-on proxy. One thing I did do was swap a legacy adapter for a synthetic one and that *did* improve things, but not as much as I would have liked. – Mark Henderson Nov 21 '11 at 00:42
  • And there's nothing going on with the host -- memory oversubscription, or dynamic memory that's favoring the other child partitions over this one? – Yolo Perdiem Nov 21 '11 at 01:39
  • @evilensky - nope. It's a new server with a buttload of RAM and almost no VM's on it yet. Total of 12 cores with virtually no CPU load, and fixed memory (even if it is only 512Mb). Other VM's on there (windows ones) have <1ms latency. – Mark Henderson Nov 21 '11 at 01:54
  • wtf? Problem has gone away on its own now. Sorry for wasting everyones time. – Mark Henderson Nov 21 '11 at 02:00

4 Answers4

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Since it's a new system, it may have needed to download and install quite a few updated packages. If the slowness is still present, try doing something like

ps -ef|grep apt

on the virtual machine to see if there's an apt-related process running. If the slowness suddenly resolved itself, it's worth checking /var/log/dpkg.log to see if a bunch of packages were installed, causing the slowness.

Conspicuous Compiler
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This problem has gone away on its own. Sorry I don't have a better answer than that.

I realise this is like pushing the green button but as this is not a mission critical production machine, I'm going to count my blessings and move on.

For what it's worth, switching to a synthentic NIC rather than a legacy NIC made a huge difference, but did not alleviate the problem completely.

Mark Henderson
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2

Old thread but still a reply; make sure after installing you remove the nic and then add a 'synthetic NIC' within Hyper-V. Ubuntu has the correct drivers for it and as far as I know it will use paravirtualization that way. Also on Windows guests OS'es you'll really want the synthetic NIC.

Robert
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Are hv_netvsc, hv_blkvsc, hv_storvsc and hv_vmbus kernel modules loaded on the guest? I run Ubuntu 10.04 under Hyper-V and ping is under 1ms. You can check modules using sudo lsmod | grep hv command.

Alex
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  • Yep, all loaded. The problem has just gone away on its own in the last hour or so after doing absolutally nothing to it (I went out to lunch and came back). – Mark Henderson Nov 21 '11 at 02:02