[openstack-dev] [nova] [bug?] live migration fails with boot-from-volume

Chris Friesen chris.friesen at windriver.com
Mon Mar 10 18:54:31 UTC 2014

On 03/08/2014 02:23 AM, ChangBo Guo wrote:
> Are you using  libvirt driver ?
> As I remember,  the way to check if  compute nodes with shared storage
> is :   create a temporary file from source node , then  check the file
> from  dest node , by accessing file system from operating system level.
> And boot from volume is just a way to boot instance , not means  shared
> storage  or not .
> For non-shared storage , have you try  block migration  with  option
> --block-migration ?

Using block migration does seem to work.  However, it passes 
VIR_MIGRATE_NON_SHARED_INC to libvirt in the migration flags, which 
doesn't seem ideal for boot-from-volume.   I assume it starts to do an 
incremental copy but then decides that both are identical?

This raises an interesting question.  Why do we even need the user to 
explicitly specify --block-migration?  It seems like we could just test 
whether the instance storage is shared between the two compute nodes and 
set the appropriate flags automatically.


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