GEO Clustering Windows Server 2008 & SQL Server 2008

Question

We have been ask to do a proof of concept for Windows & SQL Server 2008 running in a GEO cluster.  Problem is we find a lot of conflicting information on how to configure it like it has to be in the same subnet etc.  We have a storage vendor that is certified for this configuration we just need more detailed information on the actual configuration and install.  We have the storage replicating it is more about how do we setup SQL Server to recognize the storage at the DR site and how do we setup the heart beat then test failover.  We have read most of the documentation out there but it is two high level to figure out exactly what we need to do.  Has anyone out there actually accomplished this and what were the steps in getting it configured and tested.

Answer 1

This will depend upon the storage vendor.  They should have some documentation or someone available to give you some support.  I know with SteelEye DataKeeper we basically replace the Physical Disk resource with a DataKeeper resource.  The DataKeeper resource is a storage type resource so the cluster setup is pretty much identical to when you use a Physical Disk resource.

You are correct in the the nodes need to be in the same subnet as this is a limitation of SQL rather than failover clustering.  You will also have to set up a majority node set with file share witness quorum (assuming you have a 2-node cluster).  You really need to understand the implications of this type of quorum as the recommended best practice is to have the file share witness in a 3rd location in order to have automatic failover in the event of a site loss.  Here is a great article that explain why http://msexchangeteam.com/archive/2007/04/25/438185.aspx

Again, your best resource will be your replication vendor.  What solution did you choose?  Have you asked them yet?

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David A. Bermingham Director of Product Management http://www.steeleye.com

Answer 2

Thanks, we are using NetApp who is an approved storage vendor.  On their side they provide the SNAP Manager to replicate the data and provide scripts to take the replicate storage to an online state when a failover happens so you can connect the DR site to it.  We have engaged Microsoft and we are working directly with them.  They're telling us that you can use two different subnets with SQL Server but I should know for sure later today.  The problem with using one subnet is that this is not realistic in most cases especially when you are running across data centers that are thousands of miles away from each other.  Most customers NOC will not allow you to setup things like tunneling to facilitate the subnet in both environments across routers.  The problems from there are how to attach the storage on the DR site in the first place if it is offline until it fails over.  We understand the Quorum in detail and all of the four different configurations including setting it up with a witness server.  Installing and setting up a cluster environment is pretty straight forward for all of the configurations but putting it into a GEO/Stretch/Multi-site cluster bring in a lot of details that we couldn’t find information for.    We will figure this out and when we do I will put together a step by step white paper which I hope will help others who are trying to do this.  As they say the devil is in the details.  Maybe this level of information will provide a clearer pictures of where we are at.

Answer 3

Thanks David, let us know how you make out.  Setting up a SQL mult-site cluster that fails between subnets a hot topic ever since Windows Server 2008 failover clustering came out.  It seems that even though WSFC supports failing an IP resource between subnets using the "OR" feature, the SQL server team has been a little behind in releasing an update to SQL Server that takes advantage of this feature.  Hopefully your guys at Microsoft have a way around that limitation.

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David A. Bermingham Director of Product Management http://www.steeleye.com

Answer 4

So we worked through this problem and basically Windows 2008 can support this at the cluster level but SQL Server can not as you stated above the OR feature is the problem.  If you configure that SQL Server hangs and does not start up.  Microsoft verified this and said they expect a fix in R2.  We can code around this and will work on that next week.  I will updated it as soon as we complete testing to make sure we have nailed. 

Thanks for your help.  

Answer 5

That would be great if it was fixed in SQL 2008 R2.  As of Tech-Ed 2009 though I was told that this was not going to be fixed in SQL 2008 R2 but at a point after that release.  Hopefully they have received enough feedback to make them change their mind :)

If you script around it it might help other people to post your final solution.  Good luck!

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David A. Bermingham Director of Product Management http://www.steeleye.com

Answer 6

That is correct. Windows Server 2008 introduced OR specifically for geographically dispersed clusters. SQL Server 2008, including R2 as of the CTP, does not support the OR functionality and as such, you must do traditional VLANs for a geographically dispersed cluster. You shouldn't expect that MS will fix this in SQL Server 2008 R2. While there is a chance they may (don't count on it since it has not been announced as one of the new things in R2), R2 is also not what is out there now, so if your deployment needs are for now, you must abide by what is technically possible today, not tomorrow.

If you code around it, make sure MS will still support you.

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Allan Hirt Blog: http://www.sqlha.com/blog Author: Pro SQL Server 2008 Failover Clustering (out now!)

Answer 7

Allan,

Thanks for you  assistance on this.  BTW, not having any experience with 2008 Clustering it was your book that made it easy for the team.  HUGE HELP!

Answer 8

What did you wind up doing?  Create a VLAN?

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David A. Bermingham, Director of Product Management, SteelEye Technology

Answer 9

That would be great if it was fixed in SQL 2008 R2.  As of Tech-Ed 2009 though I was told that this was not going to be fixed in SQL 2008 R2 but at a point after that release.  Hopefully they have received enough feedback to make them change their mind :)

If you script around it it might help other people to post your final solution.  Good luck!

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David A. Bermingham Director of Product Management http://www.steeleye.com

Could you give more explanation on it? Where can I find the related documentation? Thanks very much!

Answer 10

Could you please share the step guidile for the setup of GEO cluster on the same VLAN.

Rgds

Arun

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Arun Khatri

Answer 11

I think you saw this on the other thread, but here it is again.

http://clusteringformeremortals.com/2009/10/07/step-by-step-configuring-a-2-node-multi-site-cluster-on-windows-server-2008-r2-%e2%80%93-part-3/

Dave

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David A. Bermingham, MVP Senior Technical Evangelist, SteelEye Technology

Answer 12

Dear David:

Is it possible to get the demo verion of steeleye software download for Geo Cluster so that we can tested on our lab & will pick it upto market.

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Arun Khatri

Answer 13

Arun,

Request trial software here http://www.us.sios.com/form.asp?i=4&contentID=56 

Make sure you mention that you have been in discussions with me and I will try to facilitate the evaluation for you.

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David A. Bermingham, MVP Senior Technical Evangelist, SteelEye Technology

Answer 14

David:

I have requested for the Demo, could you please escalted & arrange asap. We will start the marketing once the test is done & my mgmt is convienced.

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Arun Khatri

Answer 15

Arun,

I have confirmed that your information was received and was passed on to a partner that handles your region.  Please let me know if you do not hear from someone soon.  Thanks!

Dave

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David A. Bermingham, MVP Senior Technical Evangelist, SteelEye Technology

Answer 16

Although I'm not the guy you're asking the question to I struggled with the multi subnet problem for some time with SQL2008 the other day.  Although I'm not entirely happy with the solution I ended up creating a somewhat limited domain account with priveleges to alter the cluster configuration on my geo cluster and a combination of that, a generic script resource, psexec with the no eula option, and a cluster config command followed by a small delay set as a dependency on my cluster IP has allowed me to simply have a single IP which is reconfigured to a valid one on for whichever site SQL is being activated on.   I reduced the TTL property on the network name and it has worked well in testing.

Answer 17

Any chance you want to share the details of how it all comes together in a blog post?  If so, I'd love to share your post on my blog www.clusteringformeremortals.com

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David A. Bermingham, MVP, Senior Technical Evangelist, SIOS Technology Corp