Live Migration Archives

July 7, 2015

Defending Fort SQL Server

I’m seeing a common theme with a subset of our customers. It goes something like this: An enemy horde is on the horizon and the database team has banded together and barred the gates of Fort SQL Server to keep it at bay or die trying.

Unfortunately, the enemy is “change” and the DBAs have about as much chance of winning as cocker spaniel does in a fight against a pack of velociraptors. It really is just a matter of time.

The particular change du jour that some are stalwartly resisting is the encroachment of virtualization into the hallowed halls of SQL Server. This puzzles me because virtualization is a potentially beneficial change. However, conversations along those lines usually result in a “Keep that virtualization away from my SQL Server!” cry from these DBAs.

In computer history terms, virtualization is by no means a “new” technology. It’s been around for more than a decade. It has already been accepted as the foundation of the modern datacenter and the secret sauce for both public and private clouds. It is also the queen of the fully automated test environment.

Logic, logic, wherefore art thou logic? Can virtualization really be good for everything else, but not good for SQL Server?

Our customers that embrace virtualization and allow us to help them tend to find that it:

Adds almost no overhead (1-2% in most cases)
Provides some nice options for building (and rebuilding in DR scenarios) standardized servers from templates
Gives the only type of failover (either vMotion of Live Migration depending on your invading virtualization horde of choice) that keeps SQL Server’s hard earned self-tuning knowledge
Increases the available options for server consolidation which usually improves both hardware utilization and HA/DR options

That is not to say that the pathway to virtualization is a cakewalk which doesn’t have its challenges. Typically, there is new knowledge to be gained and new skills to master. Service monitoring becomes a must have to thwart the “noisy neighbor” scenario and other resource conflicts. At many companies, the DBAs become more reliant on the IT operations staff for certain tasks they previously owned – up to and including some types of failover. However, none of these is by any means terrifying to IT professionals. This is partially because no other field progresses as fast as computing, and over time we’ve gotten used to the pace of our changing technologies.

My business partner Allan has also seen quite a few of these SQL-under-siege situations. It is one of the main reasons that we are teaming up for a talk about virtualizing SQL coming up on Wednesday July 8 at noon EDT for the PASS Virtualization virtual chapter (http://virtualization.sqlpass.org/). If you are interested, please join us there. Click here to register.

Our goal is to help you understand what long-term benefits Hyper-V brings to the table so you will be leading the team doing the planning and deployment. In the end, a great Hyper-V implementation the best defense of all.

November 4, 2011

SQL Server 2012 High Availability and Editions: Basic vs. Advanced

It was hard to miss the licensing and edition announcements for SQL Server 2012 yesterday. This post won’t touch on those too much. Others (such as Denny Cherry’s blog post or Geoff Hiten’s blog post as examples) cover that pretty well. I will say these three things, though:

Anyone who is surprised by the license by core and not socket should not be. It’s been a long time coming. Am I shilling for MS here? Not at all. I’m shocked MS hadn’t changed it years ago based on the way the industry itself has been going. I will still argue that if you do the math, in most (if not all) scenarios you’ll still be cheaper than competitor solutions. SQL Server does give you really good bang for the proverbial buck with a lot of features “in the box” no matter what edition you choose.
In terms of cores, understand this and you’ll be in better shape to understand cost: there is a minimum of 4 cores to purchase for each individual processor. What that means is that if you have dual core processors (i.e. a physical processor with 2 cores), you are still paying what you would pay today. 4 cores in SQL Server 2012 is the equivalent of a single processor in SQL Server 2008 R2 and earlier. After 4 cores, you buy licensing in 2-core “packs”, so if your intended server has processors with 6 cores, it winds up being 1.5x what you pay today.
I know some folks liked all the different variations of SQL Server. I mean, who wasn’t looking forward to SQL Server 2012 Titanium Edition (available only for a limited time)? All kidding aside, Microsoft isn’t a camera manufacturer that can just change its shell to another color or textile and charge you more as much as some camera companies (*cough* Leica *cough*) do. I think simplifying down to three editions (Standard, Business Intelligence, and Enterprise) keeps things much, much cleaner and easy to understand. Enterprise vs. Datacenter did confuse some, so I’ll say this one is a big net positive.

The one thing which some may have noticed is the line on the bottom of the chart linked above for editions: Enterprise has “Advanced” for high availability and the other two have “Basic”. What exactly does that mean? Thanks to MS for helping me to clarify. The list below is as things are today. Things may or may not change between now and whenever SQL Server 2012 RTMs.

Basic

Synchronous database mirroring (same as it is now in current Standard)
2-node failover cluster support for an instance (same as it is now in current Standard)
Log shipping (same as it is now in current Standard)
Replication (same as it is now in current Standard)
Mobility limitations removed for Standard/BI, so Live Migration now really a good option for VMs if you have Software Assurance (so not new, but kinda new)
Support for Server Core deployments (new to SQL Server 2012) – both clustered and standalone

Advanced (which includes everything you get in Standard/BI plus …)

AlwaysOn availability groups and everything that comes with it like readable replicas, backups from replicas, PowerShell cmdlets, etc. (new feature in SQL Server 2012)
Faster failover for clustered instances (new to SQL Server 2012 – talked about this in my PASS Summit preconference)
Peer to Peer replication (same as it is now in Enterprise and Datacenter)
> 2 node failover clustering (same as it is now in Enterprise and Datacenter)
All modes of database mirroring with automatic page repair (same as it is now in Enterprise and Datacenter)
The various online operations such as index rebuilds (same as it is now in Enterprise and Datacenter)

In essence, outside of the new AlwaysOn availability groups feature exclusively in Enterprise, the split is pretty much what you get now: a more feature rich high availability set in the top edition, and less in the others. Don’t let the names Advanced and Basic fool you – it’s just marketing terminology (much like AlwaysOn [with no space] is a branding thing).

The only slight bit of disappointment I have to be honest is twofold:

While I thought availability groups would be Enterprise only, I was hoping they would do something akin to what they did with database mirroring and put a more limited form in Standard and everything in EE. That didn’t happen. Let’s hope in a future version after 2012 it will.
Along the same lines, if availability groups were going to be EE only, I hoped that Standard would get the full database mirroring implementation. There’s precedent for that (see: log shipping [EE only in 2000, all in 2005] and backup compression [EE only for backups in 2008, all in 2008 R2]) as newer features get introduced or times go on. That also didn’t happen here. That’s more of a disappointment to me than AGs not being in Standard/BI.

These are not things to start a letter writing campaign to Microsoft. I’m just expressing my own personal opinion as someone who is obviously close to the HA feature set. I still think SQL Server 2012 has a compelling offering for most that if you are starting to consider upgrades or new implementations, seriously start evaluating it in its current form (CTP3).

Do I Need the Enterprise (or Datacenter) Edition of Windows for SQL Server 2012?
The answer to this one is “it depends”. If you plan on deploying AlwaysOn availability groups or failover clustering, yes. I know I haven’t talked about availability groups much but I’ve been working with them for awhile and some of what I know is still under NDA and I’d rather be able to tell everything. Anyway, availability groups require that the OS is clustered but SQL Server does not need to be (but you can cluster it if you want). Based on what I said above for Basic vs. Advanced, if you are not using SQL Server Enterprise, you won’t need to worry about choosing EE or DC for Windows anyway since you won’t be getting the availability groups feature.

The need for at least Windows EE has been a bit of a controversy for some as they want to, say, do clustering with SQL Server Standard but need a higher edition of Windows since Windows Standard does not support failover clustering – it’s not a 1:1 ratio (so-to-speak). Is there a cost difference? Absolutely. However if you look at the cost of the Standard vs. Enterprise editions of Windows, it’s not the same difference at all as it is with SQL Server in terms of price. I know that even a minor difference in the amount could be a huge one for some companies; I’m not blind to economics. But if you plan on implementing SQL Server 2012 EE, it would be almost silly not to deploy at least the equivalent edition of Windows since you wouldn’t be able to take advantage of a great new feature like availability groups.

Supported Platforms
Now is as good a time as any to remind you about the blog post I wrote back in June which talks about the intended platforms you can deploy on. My thoughts there haven’t changed either, especially around supporting (or not) 32-bit.

That’s it for now … hope everyone has a great weekend!

November 26, 2009

Vmware vMotion and Hyper-V’s Live Migration – Some Quick Thoughts

It’s 3:11 AM here and I just got my first Vmware demo environment with vSphere 4 (i.e. ESX 4.0) configured to show vMotion. Having set up both Live Migration and now the aforementioned vMotion, I can tell you that I much prefer the setup under Hyper-V. Just getting vSphere installed (pretty simple using its GUI Setup) and configured (not straightforward … maybe it’s my unfamiliarity with the server-based Vmware products, but it is not intuitive like Vmware Workstation is) took me the better part of today to figure out all of the little nuances. OK, sure, I could have probably read some docs (which I wound up referencing), but setting up clustering and then Live Migration is just easier.

I also didn’t like the fact that vCenter needs a 32-bit ODBC connection to work (it uses a SQL Server backend), and it does not install the latest SQL Express version (if you choose not to use an existing instance with an appropriate DSN). That means those of you on later versions of Windows (read: Windows Server 2008 R2) will have to patch immediately. I wound up configuring vCenter Server under a Windows Server 2003 R2 VM.

As for the actual features – vMotion and Live Migration – they do essentially the same thing (migrate a virtual machine from one hypervisor host to another while keeping it up and running). They both work well.

The one major advantage of vSphere + vMotion at the moment is that I can demo it live on my laptop; my Live Migration stuff has been captured from a setup I did about a month ago when I had access to hardware. If you’re wondering why, it’s because the VT-x extensions that enable things like virtualization are not emulated in VMs (and if you think about it – it makes sense; virtualize a virtualized environment isn’t a normal use of the technology). Both Microsoft and Vmware do not emulate VT-x. To do vSphere, it seems like Vmware does something special under the covers. I hope MS does something similar because I’d love to demo Live Migration “in the flesh”.

Having said all of that, it’ll be interesting to see how I get along with vSphere now that I have it set up. Since many customers of mine are invested in vSphere/ESX for their virtual environments, it’s clearly in my best interests to have a good working knowledge of setting it up. I know DBAs probably won’t be doing most of what I do, but this work I’m doing right now helps in conversations with the other groups (especially the guys setting up the VMs). I’m not new to Vmware – I’ve been using Workstation for nearly 10 years with a lot of success, and I used Vmware Workstation 7 to set up this new vSphere 4/vMotion environment.

I have yet to play with any of the other virtualization products since quite honestly, my customers really only talk about Vmware or Microsoft. The others don’t come up in conversation. If you’re using one of the other ones, I’m not denegrating your choice – do not take it that way. It’s just that I’m not seeing it out there, much like the most common storage vendor I see at customers is EMC. There is other stuff, too – IBM, some HP, a Hitachi here and there – but EMC seems to be ubiquitous. All I care about is ensuring you have the right configuration no matter what hardware/software choices you make.

OK, off to get a few hours of shuteye and back to the grind in the AM to finish up some stuff before I head to Tokyo!

October 23, 2009

Consolidation Using SQL Server 2008 Whitepaper Now Posted to MSDN!

I’ve been talking about it for awhile, but it’s finally here – my update of the old SQL Server 2000 consolidation whitepaper. It just went live less than an hour ago.

The basic info including the link to the download of the Word document can be found here:
http://msdn.microsoft.com/en-us/library/ee692366.aspx

or you can just download the Word doc from http://download.microsoft.com/download/D/B/D/DBDE7972-1EB9-470A-BA18-58849DB3EB3B/SQLServer2008Consolidation.docx.

I hope you find it useful!

October 13, 2009

How Many Methods Can You Use to Live Migrate a VM Under Hyper-V and Failover Clustering?

The answer: 4.
1. Failover Cluster Manager
2. Move-ClusterVirtualMachineRole PowerShell cmdlet (part of the failover clustering cmdlets)
3. System Center Virtual Machine Manager 2008 R2
4. Move-VM PowerShell cmdlet (part of the SCVMM 2008 R2 cmdlets)

At the end of the day, how you perform a Live Migration is going to depend on how you like to work – GUI or command line, and then it's down to preference under those. Not everyone will deploy SCVMM, so what you get natively with Windows Server 2008 R2 in Failover Cluster Manager and its PowerShell cmdlets.

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