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On Aug 20, 2012, at 12:54 PM, Thomas Vachon <vachon at sessionm.com> wrote:

> On Mon, Aug 20, 2012 at 12:45 PM, Lorin Hochstein
> <lorin at nimbisservices.com> wrote:
>> 
>> On Aug 20, 2012, at 9:59 AM, Thomas Vachon <vachon at sessionm.com> wrote:
>> 
>> On Mon, Aug 20, 2012 at 9:57 AM, Lorin Hochstein
>> <lorin at nimbisservices.com> wrote:
>> 
>> On Aug 20, 2012, at 9:44 AM, Thomas Vachon <vachon at sessionm.com> wrote:
>> 
>> OK, I have a feeling I know at least how to "fix" the issue.  After
>> reading the entire thread, it seems to be 100% related to the
>> checksumming of dhcp in QEMU (which is broken).
>> 
>> 
>> Thomas:
>> 
>> Do you have a link to the upstream bug that describes the DHCP checksum
>> problem in QEMU? I'd like to add it to the docs.
>> 
>> 
>> 
>> This is the best one I can find:
>> https://bugs.launchpad.net/ubuntu/+source/libvirt/+bug/997978
>> 
>> 
>> Ah, that one. I tried to document that issue in the Compute Admin guide
>> under "KVM: network connectivity works initially, then fails":
>> <http://docs.openstack.org/essex/openstack-compute/admin/content/network-troubleshooting.html#d6e6602>.
>> 
> 
> I have just completed a test with Cassandra on 10.04 guests where I
> inserted 4,000,000 each on average about 512 Mb.  I never saw it dump
> the network. On average when running a 12.04 guest, I would see it
> dump out after about 4GB of writes across the cluster. This problem
> seems to be isolated to 12.04 guest QEMU code.  I still can run 12.04
> as the host, just not the guest.

I'll add to the docs that this bug appears to be specific to Precise guests.


Take care,

Lorin
--
Lorin Hochstein
Lead Architect - Cloud Services
Nimbis Services, Inc.
www.nimbisservices.com


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