Right mix of VLANs on NICs

M Anon

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Mar 11, 2025
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On a typical HP DL36x Proliant server, we have 4 x 1Gbps ports on a common NIC and 2 x 10Gbps ports on another NIC.

We plan to use the 2 x 10Gbps ports as dedicated LAG'ed ports to the storage VLAN to take advantage of 9000 MTU.

The question is more towards the 4 x 1Gbps ports. 2 of those will be LAG'ed for Production VMs. We know from the documentation that Corosync (which we understand to be vMotion equivalent in VMware) requires a dedicated NIC but it seems a waste of ports to do so and we're wondering if we can just LAG the 2 remaining ports and have Management, Corosync and backups running on it under the assumption that we're really not going to migrate VMs across clusters if backups are running.

We're using Veeam so the "backup" VLAN is actually just the manageement vlan for the proxies/workers and repositories. The workers will have a virtual NIC that will be on the storage VLAN (c/o the 2 x 10Gbps NICs) as well as the repositories so the bulk of the traffic will go over that rather than on the "backup" VLAN.

Or are we making this overly complicated and better to just use the 2 x 10Gbps and run everything off of those (less cabling, less port utilization on the switch)?
 
Corosync likes <5ms latency from what I’ve read here. The point of the separate network is just to avoid any other traffic. You can/should also add other networks in case of switch failure etc. as backups.

One can designate a migration network for copying/migrating VMs.

Hope that helps a bit.
 
@SteveITS So if Corosync is VLAN 13, Management is VLAN 11, and backups are VLAN 14 but they all go through the same LAG'ed NICs (2 x 1Gbps), they should be fine right?
 
Typical advice would be to prioritize 13 then.

Probably ok?. Migration, Ceph, etc can take a good amount of bandwidth. Backups in your case.
 
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