Understanding the network flow with PBS

[paul2000]

Hello everyone,

Unfortunately, I still don’t fully understand the network concept for the Proxmox Backup Server and hope someone here can explain it to me.

I would like to set up a three-node cluster with Proxmox, where the virtual machines are stored both locally and on an NFS storage. Dedicated physical interfaces are planned for the uplink, cluster, Corosync, and storage connection – with LACP configured for the uplink and storage.

If a Proxmox Backup Server is added as a dedicated system, how does the backup process work? Does it go via the storage link, or should a dedicated link for backups be created (how would one configure this in Proxmox)?

Thank you very much.

 

[fabian]

the connection to PBS happens over whichever route the system has configured for the IP of the PBS system (or, the IP that the hostname of the PBS system resolves to, depending on how you configure the PBS storage on the PVE side ).

if you want that connection to happen over a specific link, then the easiest way to do that is to give the PBS an IP that is routed over that link by default, and configure PVE to use this IP for this PBS system.

e.g., if you want to use your storage link, and that link has an associated subnet (like a /24), then just put PBS in that subnet and everything should work as expected.

 

[paul2000]

Hey Fabian,

thanks for your reply. So basically, it doesn't matter from a technical perspective *how* I access the PBS and the traffic always intercepts the VE nodes.

PBS -> VE -> Storage

Now, how about avoiding to use the regular storage link when I want to have a dedicated physical network just for backups? My understanding would be, that I simply create an additional physical connection between storage and VE nodes including a new subnet and place the PBS there. But when the PBS now connects to the VE nodes, how can I configure the VE nodes to only use a different interface for the backups to not have any further impacts for VMs on the storage network?

In that case it would have two ways to connect to the storage and requires to know which link to use for which case?

Thanks!

 

[fabian]

the traffic doesn't "intercept" the PVE nodes, it is the PVE nodes that generate the traffic in the first place.. the backup is running on the PVE node ater all

so yeah, if you want to use a specific link for that, just ensure that the PVE system uses that link when talking to the PBS system. if the PBS system than talks to an external storage, that needs to be handled on the PBS system.

the communication is also always initiated from the PVE side, the PBS system is not aware of any clients except when they connect to it.