serviceguard hub for heartbeat ?

[Sammy_2]

In a 2 node mcsg cluster, what is the best way to send heartbeat between nodes ?
Will regular pc ethernet hub work or do I need a HP hub ?
And will a wireless hub work or not ?

[harry d brown jr · Accepted solution]

Why not just WIRE the two servers TOGETHER and NOT use a hub???

If you have Gig-E (recommended), then any "cat 5e+" network cable will do. If you don't have Gig-E then you need a crossover cable.

And NO, wireless can not be used.

live free or die
harry d brown jr

[RAC_1]

You can have more than one heartbeat. One crossover cable, one through switch/hub.

Anil

[Sammy_2]

I have a spare GIG-E (A6825A) card in each of the boxes. Will a regular LAN cat 5 cable really work to send heartbeat ?
Also, I go with hub, will a regular PC hub work or do I need HP hub for that ?

[Jeff Schussele]

Hi Sammy,

Although I prefer to use switches, but you could use a hub. BUT you need to use *2* hubs else it would be a SPOF. I also use 2 seperate subnets - just in case. Remember HA is all about eliminating single points of failure and the heartbeats are a *very* important function that should never be a possible SPOF. You lose the HB & one of the systems is going to TOC & if that happens to be the node currently running the package(s), well, then you're going to have an outage while it halts there & starts on the other node.

My 2 cents,
Jeff

[Gary L. Paveza, Jr.]

We send heartbeats across our data network and have a decidated network for just heartbeats. I use a 5-port Linksys router for the dedicated heatbeat network - one router actually handles 2 of my clusters. It's not a SPOF since the regular data network is also a heartbeat network.

[Hilary Nicholson]

Hi,

I have used hubs in the past for a dedicated heartbeat, but also send the heartbeat out across all data lans as well, that way you have multiple redundant heartbeats.

Regards,

Hilary

[Sammy_2]

Is this true about using crossover cable on 2 node cluster ?
If either LAN cards fails, then BOTH LAN CARDS go down . Then, WHAT IS THE PURPOSE OF HAVVING 2 LAN CARDS ?




Below is from HP CE
==================================

This solution only works in a two node cluster. There is no way to
have a Standby LAN card when using a crossover LAN cable.

2. When either LAN card fails, or the crossover cable is disconnected,
both LAN cards go down. This is because the electrical signals
necessary for the cards to determine that a valid LAN connection
exists are not present.

[Patrick Wallek]

It makes perfect sense if you are using a crossover cable.

Think about it...... A crossover cable is plugged DIRECTLY into each LAN card. No routers, switches, hubs or anything between the cards on each machine, just the cable. So if a card dies, or you unplug the cable, you lose that LAN. With just the cable between the boxes you have NO WAY to have a standby LAN. There is no way for it to failover to another card automatically.

You want to have your production network going through a switch or something so you can have a standby lan card for that. But if you have a 2nd heartbeat using the crossover cable, you might not need that one to have a standby card.

[Jeff Schussele]

Hi (again) Sammy,

I think you're misinterpreting this.
The 2 lan cards - 1 in *each* node will go down. Not 2 lan cards in the *same* node.
A cable cut/disconnect would do the same thing - but that would not affect the second heartbeat connection - only the hearbeat that cable was carrying.

HTH,
Jeff

[harry d brown jr]

Patrick,

I would use a crossover cable (not necessary with gig-e) between the two nodes if I was only using one dedicated heartbeat network.

If I was to deploy a dedicated failover heartbeat network I would use a switch, not a hub.

The last cluster I built I used the data network as the heartbeat failover network with the dedicated heartbeat network using a hardwired LAN-to-LAN card cable.

Is a hub even supported in MCSG?

live free or die
harry d brown jr

[Sammy_2]

jeff,
Thanks for clarifying that. I am going to test to see if your card fail on each server using crossover cable.I intend to have 2nd hbeat

Harry,
Good thought abt using cat4 for heartbeat . But HP CE mentions
"My network specialist resources tell me that CAT5 with RJ-45 is the most
common connection cable, but for 1000Mbit/Sec transmission all 4 wire pairs
are used, whereas slower networks don't use all 4 wire-pairs. Thus, some
cables may not be completely wired for a gig-E connection."
It is a matter of perception as to what is more safproof. hub, switch, crossover cable ?
I think he said hub is supported so I will go with middle of the road solution and buy me a hub.

Patrick,
I agree switch is the best solution.
And I may use a switch but why spend extra bucks on a switch when all you are doing is sending heartbeat (hub can do that too). Any reason switch has an edge over hub for THIS purpose (heartbeat)
have to give mgmt. reason to use switch and not a hub. I am thinking of getting 10mb 4 port hub.

gary,
Like you suggested, I will also have 2 ded. network. Thanks. good advice.

Hilary, I may do what you have done. Thanks

RAC - Thanks for being one of the first one to suggest to have multiple heartbeats.

Thanks to all who answered.