Windows 2012 cluster diagram

Hi Kendra, Thanks for the reply. But I am still confused. Let me also undestand what goes to other Node say Node2 SQL02 instance when whenever failover occurs. The SQL01 instance can move from physical node to node in the cluster only online on a single node at a given time. But databases are only on ONE instance. Those do work differently and are beyond the scope of this post.

Thanks a lot Kendra…. I understood completely now. I have just read the first few paragraphs on my lunch at work and you have already saved me hours of time trying to understand what clusters are. I intend to read the rest at home. I think I seen this question kind of asked somewhere above, but not answered.

Instance-A will be Active on Node1, and passive on Node2. Please provide advice. B Node 4 — Inst. SQL Server will automatically try to balance memory usage based on activity when more than one instance is live on one node.

Want more info? Note that the article lists three approaches, and I am recommending the second one, which lets you get the most bang for your buck, but I do still recommend setting max memory. So, taking that into consideration, what really matters is the level of activity of the instances, the hardware, environment, and your requirements for performance on a given node. Four instances on a single node absolutely might not perform up to your standards if that becomes necessary, even with really good memory reservations set.

Can you elaborate as to why YOU are not a fan? If you have three physical boxes, the goal of being able to fail over to another node to help with patching could be done without using any virtualization. I was just wondering, if I need all 3 SQL Servers to be serving databases do I need 3 separate clusters on 3 instances or is it that when you add a node you can have databases on any of the nodes.

Windows Failover Clustering requires Enterprise Edition for Windows in some versions, and it also requires domain membership. If the DCs are super old then it sounds like you may be all out on your own working out issues if you start hitting strange things like unexpected failovers. Great article, I think my only question would be on the number of servers for cross-site failover.

Maybe this is more of a finacial decision, but since you have a voting system instead of the old quorum it gets very more expensive to a 2-node cluster in the primary site, you would have to only have 1-node in the DR site to facilitiy failover for the DR site.

I usually will look to have a 5-node at the primary and a number fewer than that at the DR site. I will usually use 3-nodes since the DR site would only be failed over to during testing and a true DR situation.

What are your thoughts on this? Thanks for that great article. I had a couple of questions regarding the same —. Do the two nodes have to be necessarily physically connected to the external storage? I am under the impression that it is mandatory, but am looking at alternatives.

The nodes connect to a switch that the storage is also connected to. Is this a feasible solution? Will it make a difference if the two nodes are not exactly the same specifications — physical and OS? Also, thank you for your guidance about why virtualisation is not a good idea.

Srinivas — using a switch between the servers and the storage is a totally normal solution. There can even be several switches. About different nodes — using different physical specs is not uncommon, but using different operating systems is. All of your cluster nodes need to be the same version like all WinR2 or all Win Brent, I had a unique situation happen this week.

I have a 3-node cluster, running under VMWare 5. SQL Server R2 is running on two of the nodes. One day, SQL instance 1 had a lot of memory pressure. The server immediate;y saw the change.

Unfortunately, SQL Server decided to fail off that node. This caused a bit production hit for me. Clifton — well, I can think of a few reasons that would do it offhand. But years of IT have just made me not count on that all happening all the time.

When SQL server failed over, what database attributes remain the same for all nodes? I am thinking that below properties remain the same regardless which node is running. Is this correct? Are there any other attributes remain the same? I need this info for a project to certify running SQL environment. I assumed the following properties will change in a failed over node? These properties are one of the interesting things about working with clusters.

The InstanceName will stay the same. I definitely recommend getting access to a cluster so you can test your script and validate this is working like you expect, or setting up a test cluster just for this purpose.

Thank you so much for your timely response. So the first 3 of below 4 stay the same. We sell software to clients and I have a project to work on certifying the software license. The proposed solution is to store customer database attributes in a SQL table when a new license is created.

And then every time when the software is launched, validating the licensing info stored in the SQL table against the running SQL instance. This is so that customers cannot just copy the database and be able to run the software. Licensing is always a tricky thing.

Just storing the name of the first instance that the application was running on can be a hard thing for customers, of course— what if the customer needs to move to new hardware for some reason? You get the answer right away and then you feel great about proving it. Our clusters all have fixed IP addresses. This way, the applications connect via IP address, and The applications reconnect with no issues.

I have a question. Exist a set of recommended hardware for make a physical cluster and a virtual cluster with sql server ? We work with customers to look at their needs and help them select individual hardware in consulting engagements. I understand that I will need to license both instances of SQL. We will be using the read only replica for load balancing and for HA if my primary host needs to be brought down for maintenance. Bottom line, do both instances need to have hardware resources configured in exactly the same way?

You need to talk to a Microsoft Licensing specialist and get a real quote from them. Licensing is not only a black art getting ever more complicated every year, but there is also an element of negotiation frequently. They have specialists because this stuff is so complex. Nice Article.. It was quite easy to understand.. M a beginner in DBA and would be greatful if you can provide me useful links and articles i should study to enhance my skills..

First of all, great article! The first one to start answering my questions regarding creating a highly available SQL Server cluster. This could then again be leveraged further with an SQL Server Cluster, making it possible to apply and test updates etc.

I have 2 servers configured with identical hardware with separate local attached storage for each and 1 small non storage server that could be used as a director of sorts if needed. Do not that both of these still have the SQL Server instance go offline when you fail over from one node to another, however. My question is this: Do I need or will i have benefits by configuring AlwaysOn feature? Hi, Eric. AlwaysOn Availability Groups helps you get higher availability in the event of a shared storage failure.

If you do need disaster recovery, then AGs may be for you. I get it, so basically what you are saying is that if my shared storage fails highly unlikely since I am using an HP p SAN array , my FC instances are still running but serving up data from local drive? In an individual failover cluster you will have shared storage as a single point of failure for all nodes in that failover cluster. If that storage fails, those failover cluster nodes FCI nodes are down for the count.

Always On Availability group allows you define some secondaries that use different storage outside of the failover cluster— they could use local storage, for instance. Would you recommend I go with Windows or keep it at ? Hi, Kyle. Sorry I should have elaborated more, we are leaving Neverfail and going to standard Microsoft.

The Neverfail configuration is too expensive to have duplicate storage of equal performance. This databases sits on 75 15k SAS and to duplicate that twice is just too much money. Add in our other DB serves and it is allot of money. Kyle — ah, gotcha. The clustering code has dramatic improvements, but it also involves different management techniques. Thank you so much Kendra for the article.

I have a question and hope you will let me know what I suppose to do. I have two nodes cluster and the node needs to have some work on it is a stand by node then what steps do I need to prepare before handling it over to system staff?

Do I need to stop cluster service for this stand by node at all? Thanks again. That is much more invasive, long term. Got it. Thank you so much Kendra. Always enjoy all the Web casts that you and Brent set up weekly for us and greately appreciate all the effort that you both put in to make our life easier as DBA. Hats off to both of you. Many people do put this directory on the logical drive with the Windows system files, provided there is going to be adequate free space over time seem to need more with every version of Windows.

If you are, I would still worry about that even if the sql server binaries were elsewhere. C: drive is really a SAN drive. SQL Server has no knowledge of what the source of the drives is, but it does know which drives have been presented to the cluster vs are assigned to the individual node.

My question was just what risks would be mitigated by doing this— I personally think it presents as many risks as it mitigates. An alternative would be to partition the current drive to separate OS — Pagefiles from SQL binaries, and extend them when new disks come. Brilliant post, very helpfull, great explination..

We have a three node Windows Server R2 cluster in our data center. Is this a supported configuration? Our applications only require SQL Standard and we have a lot of them, so costwise it makes more sense to have a couple of 2-node SQL Standard instances running on a 3-node cluster. Of course we are limited to cores, but that is fine for the applications we are using.

If you have a 3-node, you must run enterprise SQL Server to begin regardless of how many you intend to failover to. Whether or not is better cost wise really depends on how closely you have kept your CPU usage tied to your actual number of cores on the machine. Just looking for a real world sanity check on whether a side by side approach sacrifices future scalability etc.

Troubleshooting performance or availability problems: Oh, that gets ugly. So I urge you to consider other options. If you do go this route, work extra hard to make sure you have a very similar setup ideally identical in a non-production environment to mitigate risk and heartache. So it depends on whether you are trying to do a side by side upgrade. Aside from this whole question, you can install an instance of SQL Server r2 on a windows cluster and then install another instance within that same cluster with SQL Server They are completely separate.

Now whether or not you should do that is a different story. This is a decidedly bad way to rollout a new version. A better way would be to have a r2 cluster and then start a new cluster on completely different machines. Great article. Clearly shows the years author has spent pulling hair getting the machines going properly…. Learnt a lot! I have two servers i can setup cluster for each server one node,can i setup active-active cluster setup? The term active-active is a little misleading when it comes to SQL Server clusters.

So if MyImportantDatabase was totally read-only, that might help with load balancing. I am creating a named instance but want it to act as a default instance. So, I created the named instance gave it a different VS name than the default and set it to use port I need to migrate to two newly added nodes in the cluster but the current default will not failover two the new nodes.

I have a current configuration of a 2 node cluster one active and the other for disaster recovery with a central SAN storage.

I wanted to know , in the event that the active instance of SQL fails application only fails and not the server fails , is it possible to failover the specific instance of the application from the active server to the other? AJ — yes, the cluster uses a DNS name like myvirtualcluster and moves that name around between nodes. What are the criteria to decide for it. My other questions is since I need to uninstall my active-active clustering setup and reinstall due to license issues with the existing sql server, Do let me know how to do it.

Will simple uninstalling the sql server through control panel is enough so that I can reinstall with new SQL installer? Hi Sanjeev. Could you please elaborate to answer above questions. As its own cluster resource group? As a resource in the availability group resource? Hi Steve. Configuring that correctly would be outside of the scope of a blog comment, but check out our clustering resources which include links to books and detailed posts about configuring DTC:. This is a great article and I also took part in the webinar.

I learned so much! Thank you, thank you! I want to make sure that I understand where the tempdb should be located. The idea of a cluster is that it can fail over, but putting tempdb on the system drive is just asking for trouble.

Typically folks just use a mirrored pair of two drives for the system drives, which provides redundancy and usually enough perf for the OS. But tempdb is one of your busiest databases and two spindles— especially two shared spindles— is going to be a performance problem.

The reason for allowing tempdb on local storage is really to support folks who want to use super fast local storage for TempDB like mirrored pci-express cards or raided SSDs — the exact opposite of putting it on an OS drive. Hi there. Yes, you need Windows licenses for all the nodes in the cluster.

You have the option to use all the features of Windows on those nodes and the failover cluster service will be running — so it does make some sense.

Outstanding post. This is not the case as only one node can access the databases at one time. This post help clarify that for me. We have a two host SQL server cluster setup. Can you explain to me how to setup a scheduled job to move a SQL instance from one host to another? We want to move a SQL instance during off hours automatically. CFeyerei — why are you trying to do that? Nobody will be there to troubleshoot it.

Probably the safest way to do it is with customized powershell commands. We need to move these because we have found that it resolves an issue we are having with our analytics engine. There will be no transactions occurring or any users affected at the time of the moves, so we should be okay in that aspect. Cfereyei — interesting.

Nice explanation! It made it easier for me to understand than a purely technical explanation. Thanks for taking the time and effort to share this. The setup I have here is a single node cluster. I have a SQL named instance on it. I need to replace this named instance with a default instance. First I planned installing the default instance side-by-side, but then I need a new network name and ip address I assume for this setup. I do not want to go in that direction, so my question is: can I just deinstall the named instance, and then install the default instance, so that I can continue using the same network name for my sql cluster?

Sorry for being a bit late on the reply. Quick question: why do you need to make it a default instance? If possibly the reasoning is that you want it to be on port , you could do that with the named instance and save a lot of trouble. Dear Kendra, Tanks a lot for all your posts. My Question is about option to do SQL Fail over in instance 2 so i will have 2 instances in the same server? Why i asked this? On a failover cluster instance shared storage , you can have multiple instances running on the same physical server.

Performance may be impacted, though. Very helpful and a simple way to explain SQL cluster. I like the unicorn running on storage. Good Post!! Nice SQL cluster pictures, mine never come out that good. Unicorn is nice touch. Would be nicer if you could draw the disk drives in the array. Is there a way to recreate the CNO and any other domain-related resources without having to completely rebuild the cluster, or is a complete rebuild from scratch the only way to do it?

If this is business critical, you might choose to start a second process of building out a new environment in parallel while you work that ticket to can restore the SQL Server databases from backups and get things back online.

However, it may lead to adding some redundnacy to the design for the DC…. My host provider caused our Cluster to fail-over last week. Because it occurred very quickly they argued with me that there was no outage.

What would you say to them? I would show the SQL Server Error logs which will contain shutdown and startup events, plus the period of time during startup until recovery is completed. This may contain messages for failed logins while the databases are still unavailable, too.

So, half of the normal activity goes to each of the two machines and if one goes down, the other becomes the primary for both databases. It has worked well, but mirroring will be going away and we would like to move to availability groups anyway because we would like read-only mirror copies. Each of the two machines would still have local mirror copies of the databases on SSD — SAN is too slow for this application. Initially, one server would be the Primary for the one database and the Secondary for the other.

We would set up the other server just the opposite. Hope you like it and stay tuned! You must log in to post a comment. Skip to content. H: used for Custom. The pre-requisites for Windows and SQL failover clustering storages, network configurations, user accounts, etc. You logged in Node 1 with cluster admin account. Provide product key for your media.

Then Next 5. Then Next 6. Setup Support Rules Wait for Rules check. Then click Next 8. Privacy policy. This topic shows how to create a failover cluster by using either the Failover Cluster Manager snap-in or Windows PowerShell. The topic covers a typical deployment, where computer objects for the cluster and its associated clustered roles are created in Active Directory Domain Services AD DS.

You can also deploy an Active Directory-detached cluster. This deployment method enables you to create a failover cluster without permissions to create computer objects in AD DS or the need to request that computer objects are prestaged in AD DS. This option is only available through Windows PowerShell, and is only recommended for specific scenarios. This requirement does not apply if you want to create an Active Directory-detached cluster in Windows Server R2. You must install the Failover Clustering feature on every server that you want to add as a failover cluster node.

On the Select installation type page, select Role-based or feature-based installation , and then select Next. On the Select destination server page, select the server where you want to install the feature, and then select Next. On the Select features page, select the Failover Clustering check box. To install the failover cluster management tools, select Add Features , and then select Next. On the Confirm installation selections page, select Install.

A server restart is not required for the Failover Clustering feature. After you install the Failover Clustering feature, we recommend that you apply the latest updates from Windows Update. Also, for a Windows Server based failover cluster, review the Recommended hotfixes and updates for Windows Server based failover clusters Microsoft Support article and install any updates that apply.

Before you create the failover cluster, we strongly recommend that you validate the configuration to make sure that the hardware and hardware settings are compatible with failover clustering. Microsoft supports a cluster solution only if the complete configuration passes all validation tests and if all hardware is certified for the version of Windows Server that the cluster nodes are running.

You must have at least two nodes to run all tests. If you have only one node, many of the critical storage tests do not run. On the Select Servers or a Cluster page, in the Enter name box, enter the NetBIOS name or the fully qualified domain name of a server that you plan to add as a failover cluster node, and then select Add.

Repeat this step for each server that you want to add. To add multiple servers at the same time, separate the names by a comma or by a semicolon. For example, enter the names in the format server1. See the upgrade process discussed here for those details. The first step of my process to upgrade this cluster was to move all of the virtual machines from my first node HyperV03 to my second node HyperV The screenshot below shows the virtuals which were on the server prior to migration.

After moving the virtuals off of the server my plan was to upgrade the first node of the cluster as I had done with my SMB file share server discussed earlier in this blog post. Setup warned me that I needed to evict the node and perform a clean installation… So there went the upgrade approach.

Clean installation it is! Once I had moved all virtual machines off of the first node in the cluster, Hyper-V manager showed the configuration below. Next I shut down the cluster service, and evicted the first node of the cluster.

After evicting the node, rebooted the system and re-attempted the upgrade. As a result of the first attempt at installation I shifted from an upgrade to a fresh installation and choose my original disk to install the Operating System on.

I have made a mental note that I will eventually need to remove the Windows. On the server itself I later needed to choose a password, log into the server, change my network configuration, join it to the domain and enable remote desktop. After these steps were done the next step was to re-install the Hyper-V server role and Failover Clustering feature shown below. Next re-add the file share s to the new host on the properties of the host within the storage section.

The next step was to create a new cluster using the server which was just installed. I used a different cluster name HyperV-Cluster2 to differentiate between the new cluster and the old cluster HyperV-Cluster. VMM should see the new cluster and it will be healthy after you change the cluster reserve nodes to 0. And re-configure the network adapter hardware to match the configurations on the non-upgraded server.

For my environment, the easiest way to document the current hardware and virtual switch configuration was to take screenshots from the server in the original cluster.