New to Clustering...questions

[Daveyd123]

Right now we have 1 Exchange Server. We are going to buy 2 new servers and Cluster them and migrate Exchange from the single server to the 2 new, clustered ones.

We were going to buy 2 identical Dell PowerEdge 1850s. What are the other hardware requirements to cluster the 2 servers? Looking at Dell's site they want to attach an external storage device. Is that really necessary?

Is there any documentation on going form a single Exchange server to a clustered one?

 

[TekJunkie01]

Hi,

I'm not an expert on Exchange clustering, but I am very familiar with web NLB and db FO clustering.

As far as I can tell, you do need an external storage device. Clustering works by having what is called a "quorum" resource which contains, essentially, a small db that the cluster nodes use to keep track of resource ownership and configuration data. One machine will "own" the resource (exchange db in this example), which will also exist on shared media. This media is usually a SAN based media, and can be very expensive. The main requirement here is that the external media MUST appear as a physical drive on each clustered node - mapped drives and UNC paths will not suffice for this.

A+, N+, MCSA:Messaging, MCSE

 

[Daveyd123]

So, there is no way to not use an external storage device and just use the storage of the 2 clustered servers?

 

[TekJunkie01]

No, not that I know of. I may be wrong, and others will chime in and say so if thats the case, but I'm almost certian you need the shared storage. You can use a distributed quorum for for web hosting in which there is no shared storage (no write scenario), but not for DB's. Any write-enabled clustering requires shared storage.

A+, N+, MCSA:Messaging, MCSE

 

[mrdenny]

TekJunkie01 is correct, a shared storage device is required to make a cluster work. I'm sure dell has a shared storage device they can sell you, however I don't use dell servers so I can't point you in the correct direction.

I do know that HP has clustered bundles that they can sell you where they sell you 2 servers along with an MSA 5000 or MSA 1000 as the shared storage along with the fiber and the fiber switch.

If you want to go bigger you can look into getting an EMC (or any other SAN), hwoever the bigger SANs are much more expensive then something like an MSA.

Denny
MCSA (2003) / MCDBA (SQL 2000) / MCTS (SQL 2005)

--Anything is possible. All it takes is a little research. (Me)

http://www.mrdenny.com

 

[Daveyd123]

Thanks for the input. I just got off the phone with Dell and yes, if you use the MS Clustering solution you need an external storage device. Dell does offer software (NSI I believe it was) that will work on top of MS Clustering Service and not require an external storage device. It basically replicates all data to the clustered server

 

[mrdenny]

I would think that a software option would not be be sporrted by Microsoft.

Denny
MCSA (2003) / MCDBA (SQL 2000) / MCTS (SQL 2005)

--Anything is possible. All it takes is a little research. (Me)

http://www.mrdenny.com

 

[TekJunkie01]

I would not use this solution, even if Dell claims it will work, without getting some type of eval and testing the solution under load. I am very skeptical of "replication" based solutions for DB clustering.

If you must go with Dell, I would look more into a Dell/EMC solution. It is more expensive, but with this you can lay the foundation for a SAN infrastructure. The iSCSI implementations are solid and are much less expensive than fibre. If you have the ability to look at other venders, I recommend a LeftHand device hands down.

If your data is important enough to cluster, than I would STRONGLY recommend going with a solid hardware platform and avoiding additional software entirely.

Just my 2c.

A+, N+, MCSA:Messaging, MCSE

 

[Daveyd123]

So, wither active/active and active/passive clusters require external storage?

 

[NickFerrar]

Yes, the only type of MS clustering that doesn't is NLB but that's not really clustering anyway.

Whatever you do don't run an active/active cluster anyway, especially not for Exchange else during a failover the server that's OK is going to get overloaded.

Dell PowerVault storage is fine for a 2-node cluster, Dell/EMC solutions are a big overkill unless you need massive amounts of storage or the fundamentals of a SAN for future expansion.

 

[Daveyd123]

Thanks for all the help. I think we are going with 2, Dell 1850 servers and a PowerVault 220S for external storage