----- Original Message ----- > From: "Richard W.M. Jones" <rjones@xxxxxxxxxx> > To: "Francesco Romani" <fromani@xxxxxxxxxx> > Cc: libvir-list@xxxxxxxxxx > Sent: Friday, July 4, 2014 1:11:54 PM > Subject: Re: [RFC][scale] new API for querying domains stats > > Right now we aim for a number of VM per node in the (few) hundreds, but we > > have big plans > > to scale much more, and to possibly reach thousands in a not so distant > > future. > > At the moment, we use one thread per VM to gather the VM stats (CPU, > > network, disk), > > and of course this obviously scales poorly. > > I'll just note here that a bug has been opened for virt-top, which > is similar to this. > > If a domain has a large number of disks (256 virtio-scsi disks in the > customer's case), then virt-top spends so long fetching the data for > each separate disk, it can take 30-40 seconds between updates. > > The same thing would happen if you had lots of domains, each with a > few disks, but with the total adding up to hundreds of disks. > > The same thing would happen if you substitute network interfaces for disks. > > What would help for us: > > - A way to get information for multiple objects in a single domain > > - A way to get information for multiple objects across multiple domains > > in as few API round trips as possible. I concur. Actually you also expressed our (VDSM) need better than I did. I think we are on the same boat. Bests, -- Francesco Romani RedHat Engineering Virtualization R & D Phone: 8261328 IRC: fromani -- libvir-list mailing list libvir-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvir-list