mcsg - 2 heartbeats on same subnet

[tam1]

Hi everyone

I was wondering if there is any issue configuring 2 heartbeats on the same subnet.

For a 2 node cluster where each node has 2 dedicated heartbeats:

I can linkloop & ping between the Lan2s, but not the Lan4's.

When I disable the Lan2's, the Lan4's can ping and linkloop.

Is there any issue why I cant get both Lan2's and Lan4's talking at the same time?

Thanks

node1 :
# netstat -i
Name Mtu Network Address Ipkts Ierrs Opkts Oerrs Coll
lan2* 1500 192.168.104.0 192.168.104.5 315 0 267 0 0
lan4 1500 192.168.104.0 192.168.104.6 18907 0 268 0 0

node2 :
# netstat -i
Name Mtu Network Address Ipkts Ierrs Opkts Oerrs Coll
lan2* 1500 192.168.104.0 192.168.104.7 33 0 33 0 0
lan4 1500 192.168.104.0 192.168.104.8 537 0 60 0 0

[Steven E. Protter]

Shalom,

There is no problem doing it. The cluster will function.

The problem is in reliability. If two heartbeats are on one network then one piece of network equipment can bring down both heartbeats.

That probably means loss of service.

The objective is high availability.

Ideally I run one heartbeat through a cheap switch on a private network that I might also use for Ignite boots. Any time you run a heartbeat on a general use network the risk is some windows induces traffic storm will put your cluster services down.

SEP

[tam1]

Hi Steven

thanks for getting back to me.

The 2 cards on each node are going through separate cisco switches.

I just cant appear to get them all reachable at the same time. I can either ping lan2 to lan2 (when lan4 is down), or lan4 to lan4 (when lan2 is down).

thanks

Terry

[Stephen Doud]

HP does not recommend configuring 2 discrete NICs to the same subnet on the same server.
See this document: emr_na-c01031662-1
"Does HP-UX 11.X support multiple LAN on the same IP subnet?"

And with that said, Serviceguard most likely will not work with this configuration.

[tam1]

thanks Stephen
I'll put the 2nd card on a separate subnet