----- Original Message ----- > From: "Itamar Heim" <[email protected]> > To: "Daniel Helgenberger" <[email protected]>, [email protected], > [email protected], "Allon Mureinik" > <[email protected]>, "Doron Fediuck" <[email protected]> > Sent: Thursday, October 30, 2014 8:00:52 PM > Subject: Re: [ovirt-users] Understanding Cluster / Datacenter upgrades > > On 10/29/2014 01:00 PM, Daniel Helgenberger wrote: > > Hello, > > > > I seem to have some issues understating what and when something happens > > if I change a cluster or datacenter to a higher version after upgrading > > engine. > > Maybe somebody could help me understand how this works in general and > > when features will get enabled? If possible, pinpoint it to concrete > > features added in 3.5. > > > > My assumptions learned form experience so far, upgrading oVirt 3.4 to > > 3.5; please correct if wrong: > > - New features are enabled if I set the cluster compat version to a > > newer version after upgrade > > unless the features don't need a host change, so engine may just support > them on your previous cluster level as well. > (or some even at host level upgrade) > > > - Prior to upgrading a datacenter all cluster need to run the higher > > version (seems logical). > > yes. > > > - This involves Engine database updates (?) and, more crucial, it will > > change settings and data on the storage domains. > > storage domains are only changed on DC upgrade, not cluster upgrade. > > > - Because of that, downgrade is not possible any more > > - Also, its usually safer to keep the old cluster version while using a > > newer engine version; because it is more likely to run into regressions > > with an upgraded datacenter (see regression blockers for oVirt 3.5.1). > > > > My questions so far: > > - What happens if I only upgrade the cluster and *not* yet the datacenter? > > you can use new features at host/cluster level (if any), but not DC > level (storage usually, sometimes network) yet. > > > - In case of 3.5; exactly when could I have used the new NUMA > > management? I assume after upgrading the cluster? > > because its unrelated to storage, so its host or cluster level. > > > - In case of 3.5; exactly when could I have used the new QoS settings > > (like disk profiles) - here I assume after upgrading the datacenter? > > I think while these are "storage", they only relate to VM behavior, not > to storage domains, so cluster level sounds like the right level. > doron/allon? >
Well, QoS is per disk. And storage domain is where storage 'meets' the VM for a specific disk. So from the VM point of view 3.5 cluster level is required to support the various profiles functionalities. > > > > If the the case of NUMA policy is not true but happens only after > > upgrading the datacenter, what is the purpose of the cluster compat > > version setting? I can think of making sure a certain minimum VDSM > > version is running? > > simply put: > host level (automatic) - engine may base some features on making sure > host has the right version > > cluster level - features which require all hosts to have the new version > to simplify things (we don't want to not be able to schedule a VM using > a new feature only on some hosts, so we only allow them after cluster > level upgrade. > > dc level - since storage domains (mostly), and some network definitions, > span multiple clusters, and for storage, all hosts in the DC may be > asked to perform the new storage operations, hence DC level makes sure > all hosts at DC level can do these actions. > > and no, I don't have a mapping of which features require which... > _______________________________________________ Users mailing list [email protected] http://lists.ovirt.org/mailman/listinfo/users
