June 2013 - SQLHA

June 25, 2013

SQL Server 2014 FCI Using a Cluster Shared Volume for Storage

Happy Tuesday, everyone!

If you haven’t heard, Windows Server 2012 R2, System Center 2012 R2, and SQL Server 2014 CTP1 have hit both MSDN and TechNet for download. One of the new features of SQL Server 2014 is that you can now use a Cluster Shared Volume (CSV) in addition to the other methods you already could use for database and backup storage (drive letter, mount point, SMB share, local tempdb – the last two were introduced in SQL Server 2012).

What is a CSV you may ask? Well, it’s a way to configure a single shared disk that is presented to and can be used by all nodes of a Windows Server failover cluster (WSFC) – a true shared disk. CSVs have been used with Hyper-V and virtual machines (VMs) for years. Why should you care about CSVs? It makes provisioning storage much easier. This is essentially the old PolyServe scenario where you had a shared filesystem for all of your instances. Prior to SQL Server 2014, all of the storage options (except for SMB) required that the storage was dedicated to a single instance, so each time you had to configure a FCI, you needed to get storage provisioned. Well, with SQL Server 2014 if you decide to use a CSV for all of your FCI installations on a single WSFC, you only have to allocate storage once. A CSV looks like Figure 1 in Failover Cluster Manager.

Figure 1. CSV in FCM

In Windows, a CSV is presented like it is a local disk, but it really isn’t; it’s a shared disk in the WSFC. Figure 2 shows what it looks like, which is a “pointer” to the shared disk.

Figure 2. CSV in Windows

When you are configuring the FCI to use a CSV, you will select the CSV configured in the WSFC as the disk as shown in Figure 3.

Figure 3. Selecting the CSV in Setup

The key part comes later: the Data Directories tab as shown in Figure 4. This is where you’re going to have to think. To ensure each FCI on the WSFC is different, each one will get its own unique directory on the CSV. I recommend you come up with a naming convention that works.

Figure 4. Data Directories Tab in Setup

Figure 5 shows what things look like if you were to navigate there in Windows.

Figure 5. FCI storage on CSV

The instance will look similar to one you would have configured if you used SMB – no shared disk shows up as shown in Figure 6.

Figure 6. FCI in FCM that uses CSV

This is just a quick glimpse into one of the new – and in my opinion – great options new to SQL Server 2014 that some of us have been hoping would be enabled for awhile. More on this scenario will be covered in detail in my upcoming book.

June 13, 2013

Haswell and EPT Update

Since my blog post last week (“My Problem With Intel’s Haswell Processors“), Intel has since revised the listings for the new mobile and now EPT is supported by them. I should have taken screen shots. Oh well.

Either way, the new lines of laptops or ultrabooks in the 3lb-ish area don’t support/can be upgraded to 16GB despite the processor supporting it.

June 6, 2013

Windows Server 2012 R2 for the DBA: 10 Reasons It Matters

Happy Thursday, everyone. By now, Symon Perriman has given his talk Continuous Availability: Deploying and Managing Clusters Using Windows Server 2012 R2 at TechEd North America 2013. I wasn’t there, but I’m looking forward to seeing the recording. Why do I bring this up? As a Cluster MVP (meaning Windows), I haven’t been able to talk about Windows Server 2012 R2 until things have been made public by Microsoft themselves. The curse of respecting NDAs 🙂

Windows Server 2012 R2 represents a significant step forward in quite a few areas – including Windows Server failover clustering (WSFC). Here’s what I think are some of the killer features and why they matter if you’re deploying SQL Server:

1. Dynamic Witness

When I saw this one last month, I almost stood up and did the happy dance. Quorum is a difficult topic and is going to get at least a chapter in my new book. Windows Server 2012 (no R2) introduced the concept of dynamic quorum where in most cases you could get to last man (nee node) standing with a WSFC. However, you still had to manage the witness as you went from even to odd number of votes. Dynamic witness changes that. Assuming single subnet/site for a moment, what dynamic witness brings to the table is that you designate a witness and the WSFC will bring it in and out depending on your scenario/need. For those deploying more simple SQL Server availability groups scenarios especially, this is really amazing. Dynamic witness isn’t perfect. For example, in the multi-site scenario I wish it let you pick a witness in each site and used whichever one it needed to based on cluster status, but hey, this is a big, big step forward.

2. Shared VHDX

Despite my normal caveats for clustering VMs, I’m pretty excited about shared VHDX – especially for lab scenarios. iSCSI is easy, but I can tell you from doing the labs in my HA class, some struggle with it. This will make things VERY interesting for doing labs as well as test clusters, not to mention production-based WSFCs with SQL Server FCIs. For more information, head on over and watch Jose Barreto and Steven Ekren’s talk from TechEd Application Availability Strategies for the Private Cloud. The VHDX stuff starts around 34:00 (but the whole talk is good).

3. Storage Quality of Service (SQOS)

I have to agree with Aidan Finn on this one. Yes, this is for Hyper-V and I know many of you are using VMware for virtualization (where they have had this for awhile with the Limit IOPS option). But we SQL Server types know I/O is a premium and absolutely necessary for performance. This will give admins some form of control over how many I/Ops a Hyper-V VM can have if needed. If you want to see more information, check out the TechEd presentation Windows Server 2012 Hyper-V Storage Performance (the SQOS stuff starts in around 42:55).

4. Hyper-V Usability Improvements

One of the reasons I’ve kept VMware Workstation around is that you can copy and paste both text and files from VMs easily. With Hyper-V, you need to create an ISO and mount it or have a network share. No more! With the new Hyper-V (and I assume it will be in the desktop 8.1 as well), you can now do copy and paste into and out of VMs. This is huge, especially if you need to get demos or test environments up, or if you’re in a Hyper-V prod VM and need to get a T-SQL script in. For a demo, see around 16:30 in Ben Armstrong’s talk Hyper -V – What’s New in Windows Sever 2012 R2. Great, great stuff – and about time. Thank you, Microsoft.

Another cool one is that if your underlying hypervisor is running R2 Datacenter Edition, the VMs will know and use the underlying license to activate. Ben talks about it around 8:10 in that video. This has me VERY excited as someone who creates a lot of VMs for demos and will save me considerable time. (As an aside, Aidan Finn has a great list of all the Hyper-V enhancements here).

5. Generation Two VMs in Hyper-V

While the use case may not be there for everyone and there are some limitations, v2 VMs allows you to do things like secure boot and have more streamlined VMs. For info, see the aforementioned talk from Ben Armstrong starting around 5:50.

6. The Rise of RDMA, CSV, SMB, and “Commodity Storage”

RDMA and SMB are nothing new; SQL Server has supported SMB starting in SQL Server 2012. However, the drive for more I/Ops and cheaper solutions, as well as improvements in Windows, is driving soluions to look at alternate solutions. In the SQL Server world, we see this already with things like Fusion I/O, Violin, etc. Look, I’m not saying fibre channel is dead and your SAN investments should be thrown out. But the world is changing, and it’s possible to get crazy performance with other technologies which are network based and NOT iSCSI. You should read Jose Barreto’s blog on a regular basis if you are at all interested in storage. Also check out his TechEd presentation Understanding the Hyper-V over SMB Scenario, Configurations, and End-to-End Performance. Note that he’s using sqlio to generate performance 🙂 Since SQL Server 2014 will support CSVs for FCI deployments (more on this in a later blog post and in my book), things are going to get very interesting.

7. Improved Troubleshooting/Diagnosability with WSFC

Another thing I’ll address more later, but glad to see there are more things to look at if things aren’t going right.

8. New Force Quorum Resiliency

If you manually force quorum in Windows Server 2012 R2, there are some new protections that will help prevent split brain scenarios. This is huge and solves some problems with multi-site WSFCs which are common with AGs. This isn’t a panacea for all scenarios but a major improvement.

9. Support for Simultaneous Loss of 50% in the WSFC

Prior to Windows Server 2012 R2, if you hit 50% of your voters/nodes/whatever lost, your WSFC would go down. However, with R2, you can lose 50% and still be up. This is essentially controlled by a parameter, but man, for availbility of FCIs and AGs, this is amazing.

10. Partially Removing Reliance on AD for AG and FCI Deployments

I saved one of the best for last. This is absolutely HUGE. One of the biggest problems that I see is that whether deploying an FCI or an AG with a Listener, the VCO creation process fails because of AD permissions. Clusters are very tied into AD and have been moreso since Windows Server 2008. However, with Windows Server 2012 R2, the reliance on AD is now ending if you want it to. This means that we’re going back to a Windows Server 2003-like deployment where there are no computer objects associated with cluster object names. There are some caveats, the big one being if you need Kerberos authentication you still need a VCO. This is great for those who are using SQL Server authentication mainly and no real AD stuff in SQL and not using Kerberos. This will remove a lot of complexity from some SQL Server-based WSFC deployments.

June 5, 2013

My Problem With Intel’s Haswell Processors

This week, Intel formally announced its Haswell processors. In the mobile world, this is a big deal because unlike the previous generation of processors (Ivy Bridge), this new one promises things like better battery life and better graphics. I’m all for better battery life. Part of that is they had to redesign the ultra low voltage (ULV) chips that go in many computers. They have a lower power consumption than Ivy Bridge. By the numbers I’ve seen in preliminary tests, Intel really did improve battery life.

My excitement, however, is short lived. As usual, I’m enticed by new and shiny laptops – most notably the upcoming Vaio Pro 11 or Vaio Pro 13. The Pro 11 reminds me of a cross between my old Vaio G, the older Vaio T (not the new cheapie one), and maybe a bit of the X505 thrown in for good measure. Why is my enthusiasm dampered? Virtualization.

Here’s why: one of the things I love being able to do is run Hyper-V (and sometimes ESX) under VMware Workstation. I use Hyper-V for most of my demos, but it’s easier to show some things Hyper-V related under VMware since I can virtualize the hypervisor and have nested virtual machines. Besides the standard virtualization (VT-x in the Intel world), what allows you to run a hypervisor and nested 64-bit guests is the Intel VT-x with Extended Page Tables (EPT) feature of the processor. EPT = second level address translation (SLAT) for you geeky types. This requirement is documented by VMware here.

Cue the sad trombone. According to Intel’s whiz-bang Virtualization Technology web page, with the new Haswell chips, only some of the desktop processors got SLAT support; no mobile processor did. Don’t believe me? Click here.

This is a real setback for those of us who do complex demos from time to time like nested VMs. Remoting back home is not always an option. I’m going to have to seriously consider getting another backup Ivy Bridge machine (even if it’s a small form backup like the NUC) because outside of video, I won’t easily be able to demo some things anymore starting with Haswell.

I’m also bemoaning the fate of things like ethernet ports and VGA, but those can be solved with adapters. You can’t add a feature to a processor.

My woes here really fall into 1% of the user base for a mobile processor. I realize this. But if you’re like me, this is a pause before you get all giddy over Haswell.

EDIT: See my follow up post http://www.sqlha.com/2013/06/13/haswell-and-ept-update/. Intel posted the wrong info initially.

June 3, 2013

Announcement Day: Windows Server 2012 R2, SQL Server 2014, and My Mission Critical Book

Unless you were hiding in a witness protection plan today, you may have heard two of the biggest splashes so far from Microsoft’s TechEd North America conference – the official announcements of both Windows Server 2012 R2 and SQL Server 2014. I’m pretty excited about both releases, and will be saying more in the upcoming weeks as more information becomes official. This is the problem

Having said that, you also may have noticed Microsoft’s release cadence is changing. This will not only affect how we think about deploying, upgrading, and patching, but for people like myself who write books, it may get near impossible to keep up, especially since I need to cover two products – Windows and SQL Server. It’s not like a book on mission critical SQL Server can only touch one. SQL Server and Windows are on different cycles, making it even more challenging.

This is one reason I’ve been a bit slower with the book – I’ve been sorting a lot of these issues out. I know the content is needed and people want it; that’s not my problem. The problem is finding a way to make it work where traditional publishing won’t work so you guys get updated stuff when you need it. By the time you write about one thing and get it out in the world, it may be too late. I need to be more agile than that. A little while ago I think I solved the problem. With the announcement of the platforms, now is a good a time as any to let you know what’s going to happen.

The content will cover SQL Server 2012, SQL Server 2014, most likely SQL Server 2008 R2 (to a degree … still TBD) as well as Windows Server 20008 R2, Windows Server 2012, and Windows Server 2012 R2. That’s a lot of ground to cover. Now you see why I’ve been hedging a bit. I need a content delivery model that can be updated.

What will this delivery mechanism be? There will be different things. For those who just want a more traditional “book” so-to-speak, I will be making that available and will ultimtately have it for sale in multiple places (Amazon, Barnes & Noble, etc.). That is what I would deem more “static’ and won’t be updated nearly as frequently. What I’m really excited about is how I will be updating the content and making it available.

It’s no secret that a topic such as mission critical didn’t want to be picked up by most of the publishers I talked to because they didn’t want a big book – and I understand that. But I also know the topic needs the space to breathe. Just a clustering book wouldn’t cut it now or in the future since everything is so intertwined; clustering by itself is not a solution. Having control over content and the publishing model, I can try new approaches. And what that new thing is will be a content subscription model. For that to work, I need a solid base to work from – hence me taking my time on the v1 content so I can build and update it when necessary.

What you also have to realize in all this is that self publication, while very liberating, is also very challenging. I’m figuring this all out as I go and trying to write and sort out the financials is not easy. Editing will not be cheap. Getting the content converted potentially to ePub and .mobi formats with as many graphics as I have may cost me an arm and a leg, and I’m not looking to charge you a ton, so I’m reconciling all of that. This is why I haven’t said too much but things are finally coming together.

How will it work? Well, some people may just want the “book” and no updates. I can accomodate them just fine. They can purchase the big thing when they feel there’s an update they need. However, for those who want access to the latest and greatest, there will be a yearly subscription only available exclusively via SQLHA.com that will provide any updates to chapters (or new chapters, for that matter) and such as part of that. No more waiting years in between book releases; once Windows Server 2012 R2 is out, I can finalize content and make it part of the book and you get that content as it relates to SQL Server right then and there. SQL Server 2014? Same thing.

I’ll also make beta content available prior to the v1 publication for a slight charge for those who buy direct on SQLHA.com.

I’m finalizing the pricing model but I promise it will all be reasonable and worth it. There will also be some early bird discounts, so the earlier you sign up, the cheaper it will be. I know some have been waiting for the updated SQL Server 2012 book, but what will be released is going to be much more than that. I plan on having pricing information and preorders up within a few weeks, and for those who sign up for it, beta content available soon thereafter.

I’m excited, and I hope you are too. This has been a long haul figuring all of this out, but I want the content out there just as much as you want to consume it. I mean, who else is going to be nuts enough to spend too much time talking about fun topics like quorum in depth? 🙂

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