[libvirt] [RFC PATCH 2/2] lib: Add note that bulk stats API queries may overrun RPC buffers

[Peter Krempa]

On Tue, May 23, 2017 at 10:12:06 +0200, Martin Kletzander wrote:
> On Mon, May 22, 2017 at 06:00:13PM +0200, Peter Krempa wrote:
> > Hint that the users should limit the number of VMs queried in the bulk
> > stats API.
> > ---
> > src/libvirt-domain.c | 7 +++++++
> > 1 file changed, 7 insertions(+)

[...]

> Is there a discussion about how to continue for the future?  I remember
> Michal starting some discussion, but I'm not sure whether that was about
> the same thing.  Anyway, that's just a rhetorical question so that I can
> say the two ideas I have:
> 
> 1) Just increase the limit over time.  Computers and networks are
>    getting faster, there's more storage space and memory, and so on.
>    It only makes sense to do scale other things respectively.
> 
> 2) Have a new API that streams the data back over virStream.  We can
>    then do it continuously (like every X seconds), that might help
>    management apps as well because I suspect that's how they use this
>    API anyway.

3) danpb also pointed out that we could use a chunk of shared memory to
transport the stats for local connections, so that we skip the RPC layer
altoghether and also avoid having two copies of the same data.

But that's something we need to design first.
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