Apache Clustering

I have a question about apache clusters. I know that you can run a Round Robin on the DNS server to load balance hits but it doesn't preserve sessions and such. I have seen that doing load balancing with heartbeats and clustering is the better way to go. My question is do only two servers with a single load balancer constitue a cluster/web farm?

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astorrs

NightShade03 wrote: »

My question is do only two servers with a single load balancer constitue a cluster/web farm?

Yes 2 servers serving identical content being fed by a load balancer is still a web farm

NightShade03

And it would make sense to have redundant load balancers though right?

Forsaken_GA

NightShade03 wrote: »

And it would make sense to have redundant load balancers though right?

Well, yeah. If you've got dns resolving to a load balanced IP, and the machine with that IP goes down, then the entire cluster goes dead. So configuring with some sort of failover is a good idea.

With that being said, we don't bother with it at work. Load balancers are like any other network gear, they'll go for years and years and years without being rebooted or failing. The only thing we have a redundant load balancer for is our mail cluster, our web farms are mostly running off foundry load balancers, or software load balancers (which is basically just a box running debian with ipvs)

NightShade03

Forsaken_GA wrote: »

The only thing we have a redundant load balancer for is our mail cluster, our web farms are mostly running off foundry load balancers, or software load balancers (which is basically just a box running debian with ipvs)

So instead of having the 2 servers load balance and have a heartbeat (in case on dies) you run a single server with ipvs which just does the load balancing for you on a single box?

IPVS is built into the kernel if I'm not mistaken?

astorrs

NightShade03 wrote: »

And it would make sense to have redundant load balancers though right?

Yes of course

jibbajabba

Use DRBD in conjunction with heartbeat