backup corosync link for HA Cluseter

[ladowny]

Hi All. I'm new to Proxmox. Been using VMWare so far and just decided to migrate. Setting up Proxmox HA cluster on OVH Bare Metal RISE-3 machines so I'm somewhat limited by OVH restrictions, only 2 networks cards, one for management interface and the other connected to vRack for VLAN's for Public, Local and pfsync network userd by CARP.

I have a seperate VLAN for corosync link on local vRack NIC and was wondering if it makes sense to set up a second corosync ring over the management NIC ( public IP ), so a vRack-NIC saturation can't cost quorum.

 

[longer]

Would not be wrong, ensuure low latency.

if switch support qos then you can attempt too configure the switch so that it prioritise corosync traffic.

Do not forget to configure migration network, Ideally should be on a separate nic as well:
Select datacenter -> Options -> Migration Settings -> Edit -> pull down menue -> select other network -> OK.

 

[ladowny]

Have no idea what this switch supports, no one does except OVH staff. What I use for this setup is OVH dedicated servers hosted somewhere https://eco.ovhcloud.com/en-gb/rise/rise-3/ and what they call vRack https://www.ovhcloud.com/en-gb/network/vrack/
The server has 2 physical NICs, first one is on public internet to access it, second one is connected to this vRack which is sort of virtual switch offering Layer 2 network . I can assign public IP ranges to that vrack and access these using bridge with VLAN id 0 and separate private networks with VLAN ids 2 to 4094

VLANs
- public network for VMs
- Local network for VMs VLAN ID 10
- Corosync network for Cluster syncing VLAN id 25
- Pfsync network for CARP pfsync VLAN id 20
- storage/migration network VLAN id 22

My concern is that having all that on a single 1Gbps link may delay corosync

 

[longer]

You are right, for corosync the recommendation is to have latancy below 5ms.
I would not activate HA in such setup because it might lead to a lot of fences (reboot).