Am I too late to use replication with my cluster?

[Adakis]

Hi there,

I've got two Proxmox VMs that I've config'd in a cluster, but I created each one with a ZFS storage.

Node 1:


Node 2:


I'm now at the point where I'd like to have certain VMs from node 1 replicate over to 2 and vice-versa. However, from what I'm reading/understanding, it's too late...that I would've had to add the second ZFS storage with the same name and unique config.

Is that right, and if so, what's the least painful way of making this work short of starting over (I have live production VMs on both nodes now).

 

[fabian]

if load allows it, you could move all guests to one node (use the "target storage" feature for migration), and then rename the pool on the other node (zpool export XXX, zpool import XXX YYY) and adapt the storage.cfg accordingly (dropping one entry, and setting the other one to be valid for both nodes).

if you can't run all guests on one node for lack of resources, then you will need to schedule a maintenance window, turn off the guests, rename the pool, adapt the guest configs and the storage config, and then start the guests again.

I recommend playing through the procedure in a test cluster first (can be a virtual one running in VMs as well)

 

[Adakis]

Fabian thanks so much for the reply. On the OVH1 host it's easier for me to schedule downtime of those VMs. But just so I understand the steps:

* Rename the pool - if I get all hosts using the OVH1-ZFS shutdown, do I issue "zpool export OVH1-ZFS" and then "OVH1-ZFS OVH2-ZFS"
* Adapt guest configs - would that be just going into each VM and repointing them to the renamed ZFS (OVH2-ZFS)?
* Adapt storage configs - would that mean changing the storage.cfg file?



Thanks!

 

[Azunai333]

Adapt storage configs - would that mean changing the storage.cfg file?

You could do this on the GUI, too.
- Go to "Datacenter > Storage".
- Disable (or delete) your old renamed storage (OVH1-ZFS)
- Edit OVH2-ZFS and add the other node to it.

 

[fabian]

pretty much. like @Azunai333 said, the storage.cfg changes can also be done over the UI, the rest needs manual shell/editor actions