[libvirt] 答复: 答复: Help：Can libvirt restore several xen snapshots more faster at same time?

[Jim Fehlig]

On 11/15/2017 02:36 AM, Chenjia (C) wrote:
> Dear libvirt expert:
> 	Thanks for your reply.
> 	if  we use ' virsh restore file --bypass-cache', we got the error message: 'unsupported flags (0x1) in function libxlDomainRestoreFlags'.

--bypass-cache is not yet supported in the Xen driver. Should be easy to add, 
patches welcome :-).

> 	By the way , May be our goal is not  make it clear to you, add argument:'--bypass-cache'  means ' avoid file system cache when restoring', it means if we restore one state file for the second time , it will be more slower than normal , because IO is slower than cache, am I  right?

But you don't restore from the *same* file right? You restore VM1 from state- 
file1, VM2 from state-file2, etc., correct? Restoring from the same state file 
twice would result in 2 instances of the same VM. Actually, the libvirt Xen 
driver does not even allow this

# virsh start test-hvm
Domain test-hvm started
# virsh save test-hvm /tmp/test-save.img

Domain test-hvm saved to /tmp/test-save.img
# virsh restore /tmp/test-save.img
Domain restored from /tmp/test-save.img
xen81:~ # virsh restore /tmp/test-save.img
error: Failed to restore domain from /tmp/test-save.img
error: Requested operation is not valid: domain 'test-hvm' is already active

Regards,
Jim