[Xen-devel] live saving of domU

["Jayesh Salvi" <jayeshsalvi@xxxxxxxxx>]

Hi,

Could anyone tell me, why 'xm save' has live parameter set to false by default. From yesterday's patch ([PATCH] [XenD] Migration-related change) i guess this paramter is renamed to network.

This is the piece of code I am talking about:
XendDomain.py:
   def domain_save(self, domid, dst):
        """Start saving a domain to file.

        @param dst:      destination file
        """

        try:
            dominfo = self.domain_lookup_by_name_or_id_nr(domid)
            if not dominfo:
                raise XendInvalidDomain(str(domid))

            if dominfo.getDomid() == PRIV_DOMAIN:
                raise XendError("Cannot save privileged domain %i" % domid)

            fd = os.open(dst, os.O_WRONLY | os.O_CREAT | os.O_TRUNC
)
            try:
--->                # For now we don't support 'live checkpoint'
--->                return 
XendCheckpoint.save(fd, dominfo, False)
            finally:
                os.close(fd)

I am interested in saving the state of a virtual machine to a file, but want to continue it running. I want to backup the state of the machine, so I want this to be unintrusive operation. I would like to pause the domU and save it to file but keeping it still in memory. After save to file is done I will unpause the domU.

I don't see why this shouldn't be possible if live migration works so well. 

Is it possible? Are there any hidden xm options for doing live save, if not where can I tweak this?

Please let me know.

Thanks,
-- 
Jayesh
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