Re: [Qemu-devel] segfault while booting from saved snapshot

[Shehbaz Jaffer]

On Tue, May 13, 2014 at 2:08 PM, Kevin Wolf <address@hidden> wrote:
> Am 13.05.2014 um 10:20 hat Shehbaz Jaffer geschrieben:
>> Hi,
>>
>> Could anyone please give me the command to do live-migration to to a
>> file? I have tried searching on QEMU Wiki but all the articles that I
>> have come across point to snapshotting the disk, and not the entire VM
>> to a file.
>
> In the HMP monitor: migrate "exec:cat > /tmp/vmstate"
>
Thanks, It worked.

For others who want to do the same please note:
We can load the vmstate saved earlier appending:

-incoming "exec:cat /tmp/vmstate"

to the command while launching the new VM.

> Kevin
>
>> Appreciate your help.
>>
>> Thanks,
>> Shehbaz
>>
>> On Sat, Apr 19, 2014 at 11:07 PM, Shehbaz Jaffer
>> <address@hidden> wrote:
>> > Thankyou for your reply. Live migration does seem like an interesting 
>> > option
>> > to explore. I will look into it and get back if I get stuck.
>> >
>> >
>> > On Wed, Apr 16, 2014 at 6:16 PM, Kevin Wolf <address@hidden> wrote:
>> >>
>> >> Am 15.04.2014 um 16:55 hat Shehbaz Jaffer geschrieben:
>> >> > Thankyou for your reply. I do not face the error using qemu.1.7.1
>> >> > version.
>> >> >
>> >> > 1 quick question:
>> >> >
>> >> > I want to create a qcow2 image file after my VM has completed booting;
>> >> > i.e.,
>> >> > when I boot from this new snapshot, I should directly get to my VMs
>> >> > login
>> >> > prompt. How can i create such a qcow2 snapshot?
>> >> >
>> >> > I tried stopped the VM using QMP after the VM had completed booting, and
>> >> > then
>> >> > using host CLI to create a qcow2 image :
>> >> >
>> >> > qemu-img create -b ubuntu.qcow2 -f qcow2 newsnap.qcow2
>> >> >
>> >> > This created a new qcow2 file - newsnap.qcow2 on top of ubuntu.qcow2,
>> >> > however
>> >> > when I boot using newsnap.qcow2, It takes me again through the complete
>> >> > boot
>> >> > process - till the login prompt.
>> >> >
>> >> > Is there a way to create the qcow2 snapshot after VM has completed
>> >> > booting?
>> >>
>> >> The reason for this is that you only create a snapshot of the disk this
>> >> way, not of the VM state (i.e. RAM contents, device states, etc.)
>> >>
>> >> The most convenient way when you're using qemu directly is probably
>> >> using internal snapshots. This is what the savevm/loadvm HMP commands
>> >> provide (not sure if there is a QMP equivalent); you can also use the
>> >> -loadvm command line parameter to start a VM from a snapshot.
>> >>
>> >> Another option is that you take an external snapshot in a new qcow2 file
>> >> like you did, but you additionally do a live migration into a file. When
>> >> restarting the VM, you need to use the -incoming option and feed that
>> >> file back to qemu. As this is a bit more cumbersome, this is probably
>> >> more an option for management tools than for manual use.
>> >>
>> >> Kevin
>> >
>> >
>> >
>> >
>> > --
>> > Shehbaz Jaffer
>> > MTS | Advanced Technology Group |  NetApp
>>
>>
>>
>> --
>> Shehbaz Jaffer
>> MTS | Advanced Technology Group |  NetApp



-- 
Shehbaz Jaffer
MTS | Advanced Technology Group |  NetApp