Re: XCP: sr driver question wrt vm-migrate

[yamamoto@valinux.co.jp (YAMAMOTO Takashi)]

hi,

after making my sr driver defer the attach operation as you suggested,
i got migration work.  thanks!

however, when repeating live migration between two hosts for testing,
i got the following error.  it doesn't seem so reproducable.
do you have any idea?

YAMAMOTO Takashi

+ xe vm-migrate live=true uuid=23ecfa58-aa30-ea6a-f9fe-7cb2a5487592 host=67b8b07b-8c50-4677-a511-beb196ea766f
An error occurred during the migration process.
vm: 23ecfa58-aa30-ea6a-f9fe-7cb2a5487592 (CentOS53x64-1)
source: eea41bdd-d2ce-4a9a-bc51-1ca286320296 (s6)
destination: 67b8b07b-8c50-4677-a511-beb196ea766f (s1)
msg: Caught exception INTERNAL_ERROR: [ Xapi_vm_migrate.Remote_failed("unmarshalling result code from remote") ] at last minute during migration

> hi,
> 
> i'll try deferring the attach operation to vdi_activate.
> thanks!
> 
> YAMAMOTO Takashi
> 
>> Yup, vdi activate is the way forward.
>> 
>> If you advertise VDI_ACTIVATE and VDI_DEACTIVATE in the 'get_driver_info' response, xapi will call the following during the start-migrate-shutdown lifecycle:
>> 
>> VM start:
>> 
>> host A: VDI.attach
>> host A: VDI.activate
>> 
>> VM migrate:
>> 
>> host B: VDI.attach
>> 
>>   (VM pauses on host A)
>> 
>> host A: VDI.deactivate
>> host B: VDI.activate
>> 
>>   (VM unpauses on host B)
>> 
>> host A: VDI.detach
>> 
>> VM shutdown:
>> 
>> host B: VDI.deactivate
>> host B: VDI.detach
>> 
>> so the disk is never activated on both hosts at once, but it does still go through a period when it is attached to both hosts at once. So you could, for example, check that the disk *could* be attached on the vdi_attach SMAPI call, and actually attach it properly on the vdi_activate call.
>> 
>> Hope this helps,
>> 
>> Jon
>> 
>> 
>> On 7 Jun 2010, at 09:26, YAMAMOTO Takashi wrote:
>> 
>>> hi,
>>> 
>>> on vm-migrate, xapi attaches a vdi on the migrate-to host
>>> before detaching it on the migrate-from host.
>>> unfortunately it doesn't work for our product, which doesn't
>>> provide a way to attach a volume to multiple hosts at the same time.
>>> is VDI_ACTIVATE something what i can use as a workaround?
>>> or any other suggestions?
>>> 
>>> YAMAMOTO Takashi
>>> 
>>> _______________________________________________
>>> Xen-devel mailing list
>>> Xen-devel@lists.xensource.com
>>> http://lists.xensource.com/xen-devel
>> 
>> 
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