[PVE-User] Cross datacenter HA

[Emmanuel Kasper]

On 12/20/2016 12:43 PM, Eneko Lacunza wrote:
> Hi,
> 
> Sure, I meant datacenter, sorry; I didn't realize the acronym was in
> spanish :)
> 
> So let me rewrite the question :-)
> 
> We are doing a preliminary study for a VMWare installation migration to
> Proxmox (14 hosts total, 7 in each datacenter).
> 
> Currently, customer has 2 datacenters in HA, so that if the main
> datacenter goes down, all VMs are restarted in backup datacenter.
> Storage is SAN and storage data is replicated using SAN capabilities.
> 
> What can be done with Proxmox to get the same HA capabilities? Would it
> be better to have 2 independent clusters, one in each datacenter, or a
> unique cluster with two failure domains?
> 
> I have some worries about quorum for a single-cluster, but I don't think
> Proxmox has anything prepared for cross-cluster HA?
> 
> Thanks a lot
> Eneko

Hi Eneko

Proxmox clustering uses Corosync for cluster connection, and corosync
needs a low latency link between nodes, in the 5 ms range.
If you have a direct *high reliable* fiber link between your two DC /
CPD this might work.  See this latency calculator
http://wintelguy.com/wanlat.html
In that case you could build a multi site cluster.

You could also set up HA beween your two DCs at the application level,
for instance using a bunch of stateless applications servers connecting
to a DB, where you want only need to setup HA at the DB level (Hint:
streaming replication if using PostgreSQL)