Creating ESX failsafe with two ESX servers acting as one!?

[OtimJoris]

Hi there.

Recently we bought 2 HP servers and a HP SAN. We connected these devices through fiber making use of a MSA1000. We have 2 ESX Enterprise of the latest version. Also Virtualcentrer is present and some more software that i dont know the names of right now.

What we want to realise is a situation where if the server that's running has an issue (failure, crash ed.) the other server automatically takes over and the users have no interruption. Basically some sort of a failsafe where 2 servers act as one. But we have no idea how to realise this or if this is even possible?

Schould we install on the SAN itselve and boot from there? Or should we install on the servers and let only the virtual date reside on the SAN? And how do we configure this?

Any help is welcome and greatly appreciated.

Grx,

Joris van der Struijk

[juchestyle]

Are you talking abouut zero downtime or minimal, say for example 2 or 3 minutes?

Respectfully,

Matthew

Kaizen!

[Curdasss]

HA will give you minimal downtime. The boxes will be brought up on the second ESX server from the one that crashed. However it is going to have to start the VM's on the second ESX server so there will be a disruption in your applications hosted in the VM's. In order to do this you can install the ESX OS locally or boot from SAN doesn't really matter, but the datastore for you Vm's will have to be on your SAN and shared to bothe ESX servers.

[RParker]

There is no contingency to allow 2 servers acting in concert. So each server can be a failover, but not a standby machine.

[juchestyle]

Ha will also need to recognize that there is a failure first. I wouldn't recommend booting from SAN.

Respectfully,

Matthew

Kaizen!

[dpomeroy]

Maybe you need something like this; Veritas Cluster Server for VMware ESX

Don Pomeroy

VMware Communities User Moderator

[OtimJoris]

I was indeed talking about zero downtime, but i also already read that this is a very tricky installation with a lot of caveats (if i am right).

So maby a setup with minimal downtime is a more likely setup.

But maby you can help me with some more info on both scenario's, so i can make a better case @ my project manager and that also i have an idea what i am going to run into when installing.

[Curdasss]

HA setup is simple. You create a cluster add in virtual center add your two ESX servers into it. Right click on the cluster edit settings and enable HA set failover for 1 host. There are various other "cluster" software out there. I'm not sure what the setup for these involves but I think it would be more difficult and time conuming than HA is. My opinion, I've never used them HA is good enough for my enviroment.

[fcapizzo]

Considering what ESX/VC can do right now, I think the only thing you can do to ensure the least amount of downtime with a VM is to have redundancy at the VM level. If you used something like Neverfail or Double Take, you could have 1 VM running on each of the 2 ESX hosts. 1 VM would simply act as a "hot spare", waiting to be put into use if the primary server (VM) fails or crashes. While this would keep a VM up and running as long as 1 of your ESX hosts is still up, there are a lot of extra costs (double storage, double licensing, etc.) to support this setup. It would also be another layer of complication, but if you want the highest potential uptime for your VMs, I think that would be the route.

Then again, if you're fine with about 2 minutes of downtime for a VM, HA is the way to go.