Multisite SAN and VMware Fault Tolerance

[Rogg23]

Hi,

Apologies if this is in the wrong section.

I have a requirement for two core rooms, with ESX hosts and SAN in each room.

In total I will have, for arguments sake, 200 virtual machines, with a 50-50 split, so 100 in each core room.

I want to use VMware fault tolerance to ensure machines remain operational in the event of a major failure in either core room.

I believe I can use Multisite SAN to perform this.

Please see attached diagram fo what I want to do, I know the diagram may not be accurate but I have drawn it quick just to try and explain the scenario.

What I want to know (or have assistance on) is:

Is it possible to use Fault Tolerance in this manner to have no downtime in the result of a core room failure? (the core rooms are not very far apart and use the same networks)

How does multisite SAN work, are there any articles I can read to assist me understanding this?

Can multisite SAN be either iSCSI or fibrechannel?

Thanks.

[AntonVZhbankov]

Fault Tolerance have big number of limitations and restrictions. It also requires shared storage. Actually VM residing on anther SAN is another VM.

You have to setup synchronous SAN replication and make two SANs look like one if you want seamless service protection. After that you can protect your VMs by HA and FT. Also you need to setup vCenter availability, for ex. with vCenter Server HeartBeat

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MCSA, MCTS, VCP, VMware vExpert '2009

http://blog.vadmin.ru

[Rogg23]

Thanks for the response, I knew about the synchronous SAN but was unsure if I could use this with FT. Should have made it more clear in my text and diagram.

So vCenter server HeartBeat monitors, replicates and recovers vCenter, either in Physical boxes or virtual boxes, or a combination of the two. If I have my synchronous SAN mirror, could I not just use FT for the vCenter server as well?

Also with FT, can you specify the host server in the cluster to act as the secondary?

[AntonVZhbankov · Accepted solution]

SAN should look like one single SAN to all ESXes. Doesn't matter how you do it.

>If I have my synchronous SAN mirror, could I not just use FT for the vCenter server as well?

It's possible for small environment. In general vCenter requires 2 vCPU, while FT works for uniprocessor VMs only. But do not overestimate FT, it's not universal solution and universal answer.

>Also with FT, can you specify the host server in the cluster to act as the secondary?

Directly - no. The only way - to create bind VM to some resource that's available to 2 ESXes only.

---

MCSA, MCTS, VCP, VMware vExpert '2009

http://blog.vadmin.ru

[Rogg23]

Thanks Anton.

Most helpful.

Regards,

Roger.