[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Xen-users] command 'xl migrate...' implements 'iterative pre-copy' or not ?

On Sun, 2015-11-15 at 10:40 +0800, pinviko@xxxxxxxx wrote:
> Hi,I use xen 4.4.1 and I am confused about the 'live migration'.
> According to docs,use command 'xl migrate <domain> <host>' can migrate an
> os from a physical machine to another.
> I look into file 'xl_cmdimpl.c' and other files in 'xen-
> 4.4.1/tools/libxl/' and find the migration has the following steps:
> a. setup a progress in target physical machine;
> b. exchange control messages between two machines;
> c. suspend the vm on the original machine and restart it on target
> machine.
> During this procedure,I don't see anything about 'iterative pre-copy',so
> I wonder if xl really implements it.

It is implemented in libxc, which is used by libxl which is in turn used by
xl. If you have found the code in "c." which does the suspend of the VM
then you can follow the call chain down to find xc_domain_save and

The save/restore was significantly reworked in Xen 4.6 into a more
maintainable and understandable form ("migration v2") with the same

I would _strongly_ recommend that if you are doing development work with
save/restore/migration on Xen then you use Xen 4.6 as your baseline.


Xen-users mailing list



Lists.xenproject.org is hosted with RackSpace, monitoring our
servers 24x7x365 and backed by RackSpace's Fanatical Support®.