On Nov 7, 2019 15:29, Christian Reiss <email(a)christian-reiss.de> wrote:
>
> Hey folks,
>
> I am looking at setting up a hyperconverged cluster with 3 nodes (and
> oVirt 4.3). Before setting up I have some generic questions that I would
> love to get hints or even an answer on.
>
> First off, the Servers are outfittet with 24 (SSD) drives each in a
> HW-RAID. Due to wear-leveling and speed I am looking at RAID10. So I
> would end up with one giant sda device.
Go with RAID 0 , or RAID5/6 as you will have the same data on all nodes (3 copies in total) .
> a) Partitioning
> Using oVirt node installer which will use the full size of /dev/sda is
> this still the right solution to Hyperconverged given the gluster issue?
> If I understood it correctly gluster is using empty drives or partitions
> so a fully utilized drive is of no use here. Does oVirt node installer
> have a hyperconverged/ gluster mode?
The cockpit installer can prepare the gluster infrastructure and then the oVirt cluster
> b) Storage Location
> In this 3 node cluster, creating a VM on node01 will the data for node01
> always end up in the local node01 server?
Nope , all data is replicated on all 3 nodes (or on 2 nodes when using 'replica 2 arbiter1' volumes).
> c) Starting VMs
> Can a VM be migrated or launched from node03 if the data resides on
> node01 and node02 (copies 2 with arbiter).
As gluster is a shared storage, the VMs can migrate on any host that has access to the storage (in your case any of the 3 nodes).
> d) Efficiency / High IO Load
> If node01 has high IO Load would additional data be loaded from the
> other node which has the copy to even the load? I am aware Virtuozzo
> does this.
Gluster Clients (in this case oVirt node) reads from all 3 nodes simultaneously for better I/O. Same is valid for writes.
> e) Storage Network dies
> What would happen with node01, node02 and node03 are operational but
> only the storage network dies (frontend is still alive as are the nodes).
Nodes will become unoperational and all VMs will be paused until storage is restored.
> f) external isci/ FreeNAS
> We have a FreeNAS system with tons of space and fast network
> connectivity. Can oVirt handle storage import like remote iscsi target
> and run VMs on the ovirt nodes but store data there?
Yep.
> Thank you for your time to clear this up.
> I have found many approaches out there that either are old (oVirt 3) or
> even contradict themselves (talk about RAID level...)
>
> Cheers!
> -Christian
