[SOLVED] NAS directly connected

[Frank_R]

A question about the following scenario:
On my Promox server I have 3 NIC's installed. On the 3rd NIC I want to connect a QNAP NAS directly and not go through
the switch as it does not have enough gigabit port's. If I create a separate VMBR for the third network interface,
can the NAS be addressed via the other VMBR, which are connected to the switch?

 

[Chris]

A question about the following scenario:
On my Promox server I have 3 NIC's installed. On the 3rd NIC I want to connect a QNAP NAS directly and not go through
the switch as it does not have enough gigabit port's. If I create a separate VMBR for the third network interface,
can the NAS be addressed via the other VMBR, which are connected to the switch?

Hi,
you could connect the NIC attached to the NAS as bridge port to the vmbr connected to your VMs/CTs directly. That way you are in the same network and there is no need for forwarding or routing. Or do you have a special reason why you would like to create a dedicated bridge for that NIC only?

 

[Frank_R]

In my case, it didn't work right away.

In the picture you can see how I configured the network.

As soon as I establish a direct connection between vmbr2 and the NAS, the NAS is no longer accessible and cannot be pinged, not even from the PROXMOX console.

The goal would be to connect to the NAS without any adjustments in /etc/network/interfaces.

 

[beisser]

multiple bridges with ips from the same subnet are bad on linux, simply because the system doesnt know where to send the packet if you say access 10.15.10.1. there are 2 interfaces with that subnet so it doesnt work.

what you would need to do is give your nas an ip in a completely unrelated subnet, lets say 10.15.11.0/24 and change the config of vmbr2 to match that subnet.

with that it should work.

 

[Chris]

In my case, it didn't work right away.

In the picture you can see how I configured the network.

As soon as I establish a direct connection between vmbr2 and the NAS, the NAS is no longer accessible and cannot be pinged, not even from the PROXMOX console.

The goal would be to connect to the NAS without any adjustments in /etc/network/interfaces.



View attachment 57091

As already suggested, you could attach enp3s0 as additional bridge port to vmbr1 and give the NAS an IP address in the 10.15.10.0/24 network range. By this, all hosts (physical and virtual) in the same subnet will be able to reach the NAS.

 

[beisser]

oh yeah that should work as well. will be a 2 port switch. thats an even better solution than mine

 

[Frank_R]

@Chris + beisser

Thank you, now it works . I didn't realize that two physical interfaces can be bound to one vmbr. I assumed that this is only possible with "bonding".
One more question about the transfer rate with this method. Is there a performance reduction to expect?

Frank

 

[Chris]

@Chris + beisser

Thank you, now it works . I didn't realize that two physical interfaces can be bound to one vmbr. I assumed that this is only possible with "bonding".
One more question about the transfer rate with this method. Is there a performance reduction to expect?

Frank

No, the bridge acts as layer 2 device in the OSI Network Model [0], so no significant performance impact is to expect. That is also why it makes more sense to attach it as bridge port, rather than having a dedicated bridge, as in the latter case you would need to forward you packets from one to the other, which happens at layer 3 [1].

[0] https://en.wikipedia.org/wiki/Data_link_layer
[1] https://en.wikipedia.org/wiki/Network_layer