Service Guard with nodes on different VLANs?

[Byron Myers]

My boss just asked me a strange question. Can a 2-node SG cluster be run with each node on a different VLAN? My understanding is that SG requires each node to be on the same LAN and/or VLAN.

[Karthik S S]

Yes you are right. All the nodes in the SG Cluster needs to be on the same Subnet.

-Karthik S S

[Steven E. Protter]

You can get aroudn this as follows:

The public ip address of the two server can be on different subnets.

The machines need either a private heartbeat lan or serial connection that is on the same subnet.

I'm not sure where the details such as package sharing and ip address sharing fall into the mix, I've not played with SG a lot.

I'm not sure my scenario will work, but it has possibilities. I think you are however much better off with the two nodes being on the same lan.

Now with enough NIC card's in the box, you can have the machines be on two vlan's on one card and the same vlan on the next nic card.

Interesting possibilities. I'd like to play with that in HP's performance labs.

SEP

[Chris Saunderson]

Depends exactly what you're trying to do.

Packages with IP addresses in different subnets (and possibly VLANs depending on how your network is set up)? Sure! Have designed systems to do exactly that and have the packages fail from one node to another and migrate the IP.

Servers with their base IP's in seperate VLANs should be doable, but I've neve done it myself always preferring to keep them in the same VLAN. The more I think about it, there should be no reason it can't be done, as it's the package IP's that migrate. Local LAN failover is IP neutral, the only danger I would see is that your heartbeats would need to go through a router to exchange hellos which may lead to a possibility of an unwanted TOC.

[Gary L. Paveza, Jr.]

If doing something like this, I would strongly encourage you to setup a private network just between these two nodes that is used for heartbeat. Our setup is one public IP address on each server for users to connect to (outside the package). Each package has an IP address that migrates. If I'm not mistaken, you could have some problems there because your relocatable IP addresses have to be able to map on top of your physical IP addresses. Not sure what the impact of having a physical and a relocatable on different VLANs would be (or even if it could be done). We also have a private network (using small Linksys routers) which serves as a heartbeat. No other users use this connection. We allow heartbeat to go through public as well, but we primarily rely on the private network.

[Stephen Doud]

All servers in a proposed Serviceguard cluster must share the hostname IP subnet to enable the cmquerycl command to contact each node to gather information for the cluster configuration template file.

-StephenD.

[Byron Myers]

Somehow I forgot to assign points, shame on me. But it's fixed now.