[libvirt] Live Migration with non-shared storage for kvm

Kenneth Nagin NAGIN at il.ibm.com
Tue Jan 26 09:57:25 UTC 2010

On January 5 I asked for comments on adding libvirt support for live
migration with non-shared storage on kvm.  I did not get any comments so I
am repeating my request:

Support for live migration between hosts that do not share storage was
added to qemu-kvm release 0.12.1.
It supports two flags:
-b migration without shared storage with full disk copy
-i  migration without shared storage with incremental copy (same base image
shared between source and destination).

I suggest adding these flags to  virDomainMigrate.

If I'm not mistaken qemuMonitorTextMigrate is the function that actually
invokes the kvm monitor.
Thus, it would be necessary to pass the flags to qemuMonitorTextMigrate..
But qemuMonitorTextMigrate does not have a flag input parameter.  I think
the least disruptive way to support the new flags is use the existing
"background" parameter
to pass the flags.   Of course this would require some changes to the
upstream functions that are invoked for migration.

What do you think?

Kenneth Nagin

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