Excerpts from Day, Phil's message of 2014-01-24 04:24:11 -0800: > > > > > > Cool. I like this a good bit better as it avoids the reboot. Still, this > > > is a rather > > large amount of data to copy around if I'm only changing a single file in > > Nova. > > > > > > > I think in most cases transfer cost is worth it to know you're deploying > > what > > you tested. Also it is pretty easy to just do this optimization but still be > > rsyncing the contents of the image. Instead of downloading the whole thing > > we could have a box expose the mounted image via rsync and then all of the > > machines can just rsync changes. Also rsync has a batch mode where if you > > know for sure the end-state of machines you can pre-calculate that rsync and > > just ship that. Lots of optimization possible that will work fine in your > > just- > > update-one-file scenario. > > > > But really, how much does downtime cost? How much do 10Gb NICs and > > switches cost? > > > > It's not as simple as just saying "buy better hardware" (although I do have a > vested interest in that approach ;-) - on a compute node the Network and > Disk bandwidth is already doing useful work for paying customers. The more > overhead you put into that for updates, the more disruptive it becomes. >
Agreed. The question becomes whether you should reserve a portion of your resources for updates or let them push you into over-subscription. Either way, those are business decisions. And once we have a working system and we can say "this costs X bitcoins", we can make a clear justification for somebody to spend developer time to push X downward. _______________________________________________ OpenStack-dev mailing list OpenStack-dev@lists.openstack.org http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev