Re: [Qemu-devel] [PATCH 0/4] block: Allow query stats for drive-mirror target

[Eric Blake]

On 10/28/2014 11:04 PM, Fam Zheng wrote:
> This series adds an optional bool parameter "query-nodes" to query-blockstats.
> 
> By default, if omitted, the behavior is unchanged.
> 
> If set to "true", the command will iterate through all named nodes in BDS 
> graph
> and report the statistics in a list, similarly. But the backing chain is not
> built.
> 
> This provides a way for libvirt to watch the allocation status
> (wr_highest_offset) of target image. Now, libvirt can start drive-mirror job
> specifying a node-name parameter. Thus the created target image gets a node
> name that can be queried with the new query-blockstats.

Well, only if libvirt actually starts naming the node at the destination
of a drive-mirror job (doesn't happen now, but this patch shifts the
blame from "qemu doesn't provide access to the information" over to
"libvirt hasn't yet been coded to interact with what qemu provides"), so
this is a step in the right direction.  The idea makes sense to me.

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

signature.asc
Description: OpenPGP digital signature