[CentOS-virt] (KVM) How can I migrate VM in a non shared storage environment?
dennisml at conversis.de
Thu Jun 24 18:29:19 EDT 2010
This can be useful in some cases:
With the blocksync.py script on that page you can first make a copy of the
block device while the VM is still running. Then shut down the VM and make
another run only this time you only have to copy over the bits that have
changed during the previous sync. Depending on HD/CPU/Net performance this
can reduce the downtime a bit.
On 06/24/2010 11:22 PM, C.J. Adams-Collier wrote:
> Note, the -x argument will keep the copy to a single partition
> On Thu, 2010-06-24 at 14:12 -0300, Lucas Timm LH wrote:
>> Create a new virtual machine on your storage. After this, boot some
>> Linux distribution in your new virtual machine (I like SysrescueCD).
>> Enable your ssh server, change the root password and so and back to
>> your old virtual server and type:
>> # dd if=/dev/sda | ssh root@(new_vm) "(dd of=/dev/sda)"
>> Type the root password, shutdown the old VM and reboot your new vm.
>> (PS: You don't need to shutdown the old vm to this proccess).
>> I do this everytime, I don't like copy the HD files using cp, tar or
>> rsync because it try to copy the /proc, /dev and a lot virtual
>> devices. Using dd it copies just the HD bits, the boot sector, etc.
>> 2010/6/24 C.J. Adams-Collier<cjac at colliertech.org>
>> I often use rsync -a for remote systems or cp -a for local
>> I've also used dd. You can have dd output to stdout, pipe it
>> to ssh and
>> have ssh output to dd on the other end.
>> You can also connect to a SAN device on the source and dd from
>> the local
>> block device to the SAN device.
>> Lots of ways to do it ;)
>> On Thu, 2010-06-24 at 10:52 -0400, Kelvin Edmison wrote:
>> > On 24/06/10 7:17 AM, "Poh Yong Hwang"<yongsan at gmail.com>
>> > > I have a server running CentOS 5.5 with KVM capabilities.
>> I need to migrate
>> > > all the VMs to another server with the exact same hardware
>> specs. The problem
>> > > is it is running on individual harddisks, not shared
>> storage. What is the best
>> > > way to migrate to minimise downtime?
>> > I've had good success using dd and nc (netcat) to copy the
>> contents of a
>> > disk or disk image from one machine to another, and
>> verifying the copy was
>> > successful with a md5sum or sha1sum of both the original and
>> copied disk.
>> > Kelvin
>> > _______________________________________________
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