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Re: [Xen-users] xl save/restore command

Hello Ian,

thanks a lot for the swift answer.

The solution of using xl save -p in combination with LVM-snapshot / disk file backup is also fine.

I will have a second look into it tomorrow. Could in fact be that the file was not written out to storage. Sad. Would have been a great feature... ;)

Kind regards,


On 28.08.2014 14:41, Ian Murray wrote:

From: Melanie Desaive <desaive@xxxxxx>
To: xen-users@xxxxxxxxxxxxx
Sent: Thursday, 28 August 2014, 13:04
Subject: [Xen-users] xl save/restore command

Hello everybody,

I am currently trying to figure out, what the xl commands "save/restore"
are exactly doing in case I leave the domain running after issuing the
save command.

I tested the following szenario:


Saving domain with "xl save -c <domain> <statefile>"

After completion creating a new file on domU.

Destroying domU

Restore domU with "xl restore <statefile>" -> The new file disappeared
from domU.

Shutdown domU

Recreate domU from configfile with "xl create <configfile> -> The file
is back again.


Does the save command checkpoint the domUs filesystems so that it can be
used to create kind of a snapshot?

As far as I know, xl save/restore are not storage aware. You might want to 
consider Xl save -p then then using your storage method's native snapshotting 
technique. I only use logical volumes, so apologies if that answer is incorrect 
for other storage types.

I notice there is a problem with xl save -p when using Xenified kernels such as 
CentOS 5. I wrote the -p patch but heavily under the guidance of proper devs, 
so I can't say I understood the ins and outs of it.

In terms of the scenario you describe, I would say (without futher information) 
that the new file wasn't fully committed to storage when you destroyed the domU.

Can someone point me to some in depth documentation or maybe give a
short summary, what the command is actually doing?

Many thanks in advance.

Kind regards,


Xen-users mailing list


Melanie Desaive
Brehmestrasse 52
13187 Berlin

Telefon: 030 - 202 372 00
Mobil:   0178 - 539 8725

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