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Support for snapshot of LVM backend image

 

hi, all

        As LVM backend image support was introduced in the trunk version of
nova, is there any plan to support snapshot of the LVM backend image?

        I am using libvirt and Xen, with lvm as the instance image backend.

        There are two issues when creating snapshot.

        1. when calling managedSave, libvirt complained there's no
supported function by the driver.

                "libvirtError: this function is not supported by the
connection driver: virDomainManagedSave"

        2. when actually creating snapshot, libvirt calls qemu-img, which
does not support lvm.

        As a result, snapshot status is always 'queue', and actually it's
failed.


        For issue 1, it seems that libvirt does not support "save" or
similar functions for xen, some modifications to the libvirt Xen driver
maybe help?

        For issue 2, I think the snapshot action should call lvm related
command but not qemu-img when using lvm.

        For example:    lvcreate --snapshot ..........


        Further discussions and replies are welcome.

        Thanks all


Regards


Wang Li

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