<html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class=""><div class="">Hi nova devs,</div><div class=""><br class=""></div>Have been having a good look into cellsv2 and how we migrate to them (we’re still on cellsv1 and about to upgrade to queens and still run cells v1 for now).<div class=""><br class=""></div><div class="">One of the problems I have is that now all our nova cell database servers need to respond to API requests.</div><div class="">With cellsv1 our architecture was to have a big powerful DB cluster (3 physical servers) at the API level to handle the API cell and then a smallish non HA DB server (usually just a VM) for each of the compute cells. </div><div class=""><br class=""></div><div class="">This architecture won’t work with cells V2 and we’ll now need to have a lot of highly available and responsive DB servers for all the cells. </div><div class=""><br class=""></div><div class="">It will also mean that our nova-apis which reside in Melbourne, Australia will now need to talk to database servers in Auckland, New Zealand.</div><div class=""><br class=""></div><div class="">The biggest issue we have is when a cell is down. We sometimes have cells go down for an hour or so planned or unplanned and with cellsv1 this does not affect other cells. </div><div class="">Looks like some good work going on here <a href="https://review.openstack.org/#/q/status:open+project:openstack/nova+branch:master+topic:bp/handling-down-cell" class="">https://review.openstack.org/#/q/status:open+project:openstack/nova+branch:master+topic:bp/handling-down-cell</a></div><div class=""><br class=""></div><div class="">But what about quota? If a cell goes down then it would seem that a user all of a sudden would regain some quota from the instances that are in the down cell?</div><div class="">Just wondering if anyone has thought about this?</div><div class=""><br class=""></div><div class="">Cheers,</div><div class="">Sam</div><div class=""><br class=""></div><div class=""><br class=""></div><div class=""><br class=""></div></body></html>