Q:

Manage oVirt environment

I'm starting to deploy oVirt in one of my works, and I have a lot of questions about how to manage everything when you start using it.
First I'll describe my setup.
I have three machines, two ProLiant DL360e Gen8 servers and one common PC. All of them have 1TB of storage available for the OS, and have the same partition scheme. Following this tutorial and it's second part, I've managed to setup the three machines as follows:
Clusterized storage with gluster and CTDB exporting four volumes: engine, isos, data and meta.
Meta is used to maintain coherence among the cluster, engine is used to store oVirt's hosted engine data, data is used to store VM's images and isos to store iso images for OS vm provisioning.
Hosted engine has been set up in both ProLiant servers.
What I was looking for with this setup is to be able to keep on running VM's even whith one of the ProLiants being down. So I had to set up a third machine for storage, that way, I would not lose quorum in the exported gluster volumes if one of the ProLiants goes down.
Everything seems to be working fine. So let me ask a few questions:

Wich is the recommended way to make backups of the hosted engine and VM's, so I can recover from disaster??
I have four NIC's in each server and two in the PC. Right now I'm using just one interface in each machine. Wich would be the recommended network setup for this scenario? I'm buying a new managed gigabit switch next week, so I will be able to have VLAN's working with this machines!!
Whis is the recommended way to bring the hosts down for maintenance??? One at a time and all togheter??
All the equipment is connected to a single APC SmartUPS, and I've setted up apcupsd on another host that is network connected with these three machines. Which is the recommended way to bring them all down really quickly in an event of power failure??? (I have around 35 minutes of autonomy with this UPS for the whole setup!)
Reading around, I do not remember where, I remember that someone stated that in oVirt it was recommended to leave the default datacenter and cluster as they were, and start configuring everything in a new datacenter. I remeber trying to do that, but not being able to accomplish it, because the hosts (the ProLiants) where already memebers of the default cluster, so I've started to set up my VM's in the default cluster. Is this wrong??? I do not know if I missed something important with this.

Finally, please excuse my bad english! It's not my native language!
Thanks everyone in advance!!!

A:

engine backup is done using a script aptly called engine-backup. Backing up VMs is trickier, there's a built-in API[1] but it will only be effective if you're using a host OS that is capable of libvirt blockcommit, i.e. latest Fedora or EL7.1. Otherwise, you can backup the VMs the old fashined way, using in-agent backups or stopping them to take a backup, if downtime isn't critical.
I would bond all 4 NICs using mode-4, if the switch can support that, and segregating the network into a management VLAN, VM network, display network and storage network. If you expect  storage loads to interfere, maybe break that down into two bonds, one for storage and one for VMs, display and mgmt
One at a time. When you click the "maintenance" button, all VMs from the host will migrate away, so the host can be taken down. Storage connections, during maintenance are also getting shut down.
Whatever the UPS vendor recommends, this has nothing to do with oVirt. Basically, the pre-shutdown procedure would be to take all VMs down first (so the UPS might want to trigger an API script that would issue shutdown on all VMs) and then place all hosts in maintenance, so they can be shutdown cleanly. When all hosts are in maintenance, it is safe to pull the plug
Not wrong and not right either. In the older versions, there were some hard dependencies that could break if you deleted the default stuff. Using the defaults wasn't a problem. Since it's still better to have everything properly named, it is recommended  to create your own DC and Clusters. To move a host between clusters, put it in maintenance, edit and change the cluster affinity. Activate the host - and it's in the new cluster.

Welcome to the wonderful world of oVirt :)
[1] http://www.ovirt.org/Features/Backup-Restore_API_Integration

