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OK, thank you for the sanity check.

Dan

On 01/16/2014 11:29 AM, Vishvananda Ishaya wrote:
> In that case, this sounds like a bug to me related to lvm volumes. You 
> should check the nova-compute.log from both hosts and the 
> nova-conductor.log. If it isn’t obvious what the problem is, you 
> should open a bug and attach as much info as possible.
>
> Vish
>
> On Jan 16, 2014, at 8:04 AM, Dan Genin <daniel.genin at jhuapl.edu 
> <mailto:daniel.genin at jhuapl.edu>> wrote:
>
>> Thank you for replying, Vish. I did sync and verified that the file 
>> was written to the host disk by mounting the LVM volume on the host.
>>
>> When I tried live migration I got a Horizon blurb "Error: Failed to 
>> live migrate instance to host" but there were no errors in syslog.
>>
>> I have been able to successfully migrate a Qcow2 backed instance.
>> Dan
>>
>> On 01/16/2014 03:18 AM, Vishvananda Ishaya wrote:
>>> This is probably more of a usage question, but I will go ahead and 
>>> answer it.
>>>
>>> If you are writing to the root drive you may need to run the sync 
>>> command a few times to make sure that the data has been flushed to 
>>> disk before you kick off the migration.
>>>
>>> The confirm resize step should be deleting the old data, but there 
>>> may be a bug in the lvm backend if this isn’t happening. Live(block) 
>>> migration will probably be a bit more intuitive.
>>>
>>> Vish
>>> On Jan 15, 2014, at 2:40 PM, Dan Genin <daniel.genin at jhuapl.edu 
>>> <mailto:daniel.genin at jhuapl.edu>> wrote:
>>>
>>>> I think this qualifies as a development question but please let me 
>>>> know if I am wrong.
>>>>
>>>> I have been trying to test instance migration in devstack by 
>>>> setting up a multi-node devstack following directions at 
>>>> http://devstack.org/guides/multinode-lab.html. I tested that indeed 
>>>> there were multiple availability zones and that it was possible to 
>>>> create instances in each. The I tried migrating an instance from 
>>>> one compute node to another using the Horizon interface (I could 
>>>> not find a way to /confirm///migration, which is a necessary step, 
>>>> from the command line). I created a test file on the instance's 
>>>> ephemeral disk, before migrating it, to verify that the data was 
>>>> moved to the destination compute node. After migration, I observed 
>>>> an instance with the same id active on the destination node but the 
>>>> test file was not present.
>>>>
>>>> Perhaps I misunderstand how migration is supposed to work but I 
>>>> expected that the data on the ephemeral disk would be migrated with 
>>>> the instance. I suppose it could take some time for the ephemeral 
>>>> disk to be copied but then I would not expect the instance to 
>>>> become active on the destination node before the copy operation was 
>>>> complete.
>>>>
>>>> I also noticed that the ephemeral disk on the source compute node 
>>>> was not removed after the instance was migrated, although, the 
>>>> instance directory was. Nor was the disk removed after the instance 
>>>> was destroyed. I was using LVM backend for my tests.
>>>>
>>>> I can provide more information about my setup but I just wanted to 
>>>> check whether I was doing (or expecting) something obviously stupid.
>>>>
>>>> Thank you,
>>>> Dan
>>>> _______________________________________________
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>>>> OpenStack-dev at lists.openstack.org 
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>>>> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev
>>>
>>
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