vzdump - is lvm spnapshot really created?

[felipe]

Hi,

i tried to use vzdump. it actually works. i use lvm and checked the option snapshot
the logs says: Nov 02 18:12:29 INFO: backup mode: snapshot
but with lvscan i can't see any active snapshot?
why? when do manual snapshots i can see them using lvscan....

i also noticed that the "take snapshot" option in the tab "snapshots" is greyed out on running guests (LVM) is this also normal?

thanks
philipp

 

[dietmar]

the logs says: Nov 02 18:12:29 INFO: backup mode: snapshot
but with lvscan i can't see any active snapshot?
why?

newer vzdump does not use LVM to make snapshots for KVM VMs.

i also noticed that the "take snapshot" option in the tab "snapshots" is greyed out on running guests (LVM) is this also normal?

That kind of snapshots is not supported by LVM.

 

[felipe]

i was searching but i could only find that vzdump uses lvm for snapshots...
so how does it work now on raw files (on lvm) without lvm snapshot?
is there a possibility to change settings of snapshot size or is that not necessary anymore?
if some guests have heavy writing the snapshot size of an lvm had to be quite big - if not during copy it would get invalid.
so this can not happen with newer vzdump? is there somwhere a description how it works?

thank you
philipp

 

[dietmar]

so how does it work now on raw files (on lvm) without lvm snapshot?

search the qemu-devel list archives (term backup) to find details about the implementation.

is there a possibility to change settings of snapshot size or is that not necessary anymore?

not necessary.

if some guests have heavy writing the snapshot size of an lvm had to be quite big - if not during copy it would get invalid.
so this can not happen with newer vzdump?

This cannot happen with newer vzdump and KVM VMs.

Note: container backups still use lvm snapshots