SQL Server with Mr. Denny

April 9, 2018  4:00 PM

Denny’s first public speaking event post surgery is…

Denny Cherry Denny Cherry Profile: Denny Cherry

In case you didn’t catch it, I’ve been out for a while, with good reason.  Apparently, emergency brain surgery takes a while to recover from.  I’m not back to 100% yet, but I’ll be speaking at my first event post-surgery, and it’s this weekend at SQL Saturday Orange County.  I’ll have Kris, Joey, and John with me at the speaker dinner and after party on Saturday evening.  I’ll be talking about on-prem storage and maybe a little Azure/Cloud storage as well.  Overall, it’ll be a great day to see everyone old friends and meet some new ones.  So get registered for the SQL Saturday, and we’ll see you there.


April 5, 2018  3:00 PM

5 reasons Cloudflare’s roll-out of has been a disaster

Denny Cherry Denny Cherry Profile: Denny Cherry

I get where Cloudflare was going with their DNS server, but the rollout, in my opinion, has been a disaster.

Cloudflare being the cloud

1. Caching

For starters, most people are running DNS servers at home. They may not know it, but they are.  Odds are your router is running DNS for you, and it’s probably pretty quick.  Even if your router in 40ms, CloudFlare’s DNS is boasting 15ms response times.  This first lookup is a little faster, after that, it’s all cached.  After the first lookup your computer caches the DNS entry locally, so you’re saving 25ms or so (in this example) once.

2. Profit?

Cloudflare also claims that their service stops your ISP from seeing where you are surfing on the web. It doesn’t. I spent years working for an ISP.  We were moving the packets to your website, and we knew what websites you were going to even without tracking your DNS lookups.

Cloudflare claims that they’ll be deleting the logs, and not selling any data collected by this service.  Now I don’t have an MBA, but where’s the profit? Running a global DNS service isn’t free, or even cheap. Companies don’t do this out of the goodness of their heart. They have to make a profit on services, or they pull the plug on them.  So something has to be making money, or the board of Cloudflare will get sick of funding this real quick.

3. ISPs

Several ISPs are blocking access to  I know that my ISP at home does. I get a lovely “Unable to connect” error in Firefox when I try and browse to the website running on And yes I know it isn’t my machine as it works fine when I VPN into our CoLo which has a different network provider.   There are several other ISPs that are blocking this access as well.  Years ago I worked for an ISP, and we knew where every customer went, not because of DNS, but because we were capturing the headers of the network packets so that we could find response problems on sites. It really wouldn’t be hard to tie this data back to a user. Knowing what IP you got from DNS really wouldn’t stop us from tracking you on the Internet if we wanted to.

And they do this, I assume, for reasons which are talked about in the blog post from Cloudflare.  There’s a lot of junk data being sent to these IPs, so a lot of ISPs are just blocking access to these IPs to make their life easier and safe themselves some network costs for sending that data.

The blog post that CloudFlare released tasks about how Twitter was used during the Turkish uprising and people got around the countries blocks by using Google DNS instead of the in-country DNS.

Swift Does Security on Twitter talking about CloudFlareThis shows that the blocking done by the country was lazy, not that DNS from Google fixed this.  If Turkey (or another country) wanted to block access to Twitter no matter what DNS you’re using, blocking access to (or whatever IP range comes up for the public IPs for the country that wants to block the service).

4. Login Pages

On top of that, several hotels, hospitals, convention centers, etc. use as the login page for their portal, so they block external requests for that IP.  One of the reasons that everyone uses that IP for their login page in right there in the Cloudflare blog post. That IP wasn’t publically used into this service from Cloudflare since so much junk was being sent to it. So because of that lots of people use it, or block it.   You can see this right on Twitter where SwiftOnSecurity shared a DM from a network engineer.  Should they be using this? Maybe.

We can’t expect to have every company that’s using to reconfigure their network because Cloudflare decided to start offering this service.  This is even the default for some Cisco models that are deployed around the world. I know that in a variety of hotels (and the hospital I was in last year) was their login portal for their Wi-Fi.  If I set my DNS to on my laptop and went to any of these sites, I wouldn’t be able to browse.  Stopping people from using their computer without a configuration change is a problem.

I get that the IP isn’t a reserved private IP, but there are RFCs, and there is the real world. And in the real world that IP is in use in private networks all over the world, and it’s known that it is in use.

5. Ownership

Would you be surprised to see that Cloudflare doesn’t own the IP space used by their DNS service?  I sure was.  The two public addresses that have been published are and   Those are both owned by
APNIC Research and Development, which means that APNIC could decide that Cloudflare is done and APNIC could simply shut down the service with no notice to Cloudflare or the users.  And since Cloudflare doesn’t own the IP addresses, there’s nothing that Cloudflare could do if this happens besides having a PR disaster.

Should we block?

Now I’m not saying that places should be blocking access here. But if I was a dictator looking to keep my people from getting online, there are much easier ways than blocking DNS (I’m assuming details like this are left up to some systems team somewhere).

Will all this get better? Cloudflare says that it will. I don’t see this getting much better. We’re talking about reconfiguring a large number of hotel, convention centers, hospitals, etc. with little to no benefit to them.  We as a technology community have been trying to get IPv6 in place for 20 years, that still isn’t even close to happening, and that’s a much smaller number of companies that have to reconfigure things.


April 4, 2018  7:01 PM

A new better way to buy Azure SQL DB

Denny Cherry Denny Cherry Profile: Denny Cherry
Azure, SQL

Today Microsoft has announced that there is a new way to buy Azure SQL DB. If DTUs aren’t making sense to you, you’ll be happy to know that you can now simply select how many vCores you want for your SQL DB workload.  Now this will still require that you have an understanding on your workload to use this new vCore based way to buy Azure SQL DB, but Cores are a concept that is easy for people to talk about and wrap their heads around. Now this new model is only in preview at the moment, but I’m guessing that it’ll be around for a while in preview, then it’ll go GA as this new model makes sense.

Personally, I see people moving to this new model instead of the DTU model as the vCores model is just easier for people to figure out, and explain around the office. Also, there’s no math to convert what you have today into DTUs.

Another nice benefit of using vCores for SQL DB is that if you have SA, you can use your existing SQL Server licenses to get a discount on your SQL DB pricing.   Now, this does require that you keep your software assurance current on these licenses, so that may end up eating at least some of your savings.  A lot more math will need to be done to see how this works out.

As you can see from the screenshot from the portal, you can select the number of cores that you want for your use case and the maximum size of the database for your use case.   vCores give many customers a much more scalable solution then they had used just DTUs.  You should see the new vCores in the Azure portal shortly (I can’t see them in my normal portal yet) and they’ll be available in all regions as they roll out.

The big question for people will be what makes the most sense? And that answer is going to be vCores.

The other big question that I see if how many vCores do I need for X DTUs? That answer will be a little greyer.  It’s going to take some trial and error when moving back to find the sweet spot between vCores and DTUs so that you have enough resources without paying more than you need.  The nice thing about the cloud is that you can ramp up and down quickly and easily depending on what you see as your applications response time.  For most customers, I’d recommend starting with a larger number of vCores and if performance in the portal (or SCCM if you have it) is low for that database then ramp down and see how it responds.

On top of the new vCore based solutions that Microsoft announced today, you also have your managed instance option available. The managed instance option can only be sized based on the new vCore solution as you have no option for the number of DTUs that will be supported.  Managed instances are the solution that Microsoft provides that’s between IaaS instances in VMs and SQL DB where Microsoft hosts the databases for you, and you can do most everything that you can on-prem or in IaaS, but in a PaaS model.  Realistically the only way this option was have made a lot of sense was with the vCore option that Microsoft is announcing today.

Overall I think this vCore option is going to make a lot of sense, and realistically should have been where Microsoft started from instead of DTUs.

If you are looking to move into SQL DB, DCAC can help you get there. Using either the DTU model or the vCore model.


April 2, 2018  4:00 PM

Why Don’t Universal Groups Work in SQL Server?

Denny Cherry Denny Cherry Profile: Denny Cherry
SQL Server
Locked Bike


If you’ve tried using Universal Groups in Active Directory to access your SQL Servers, you may notice that the users who are members of these groups can’t access the SQL Server Instance. The reason for this has more to do with active directory than with SQL Server. Normal groups in Active Directory are cached so authentication requests can return groups that the user is a member of as part of the Windows Token. Universal groups, however, aren’t included in the Windows Token as the Universal groups that the user might be a member of might not be in the same domain that the request is handled by.

The internals of why Universal Groups don’t work requires a decent understanding of the internals of Windows Authentication Tokens and Windows Security. But needless to say, all that you need to know is that Universal Groups don’t work with SQL Server.

Because the Universal Groups aren’t in the authentication token when the SQL Server goes to see if the user has access, the token says that the user doesn’t. The fix for this is quite easy, use a different Windows Domain Group type than Universal Groups.


March 26, 2018  7:36 PM

Azure precon at SQL Grillen in June

Denny Cherry Denny Cherry Profile: Denny Cherry

I’m thrilled to announce that we’ll be hosting a pre-con at SQL Grillen this June in Lingen, Germany titled “Designing Azure Infrastructure for Data Platform Projects” which you can see on the events schedule page. The abstract for the session is:

In this daylong session, we’ll review all the various infrastructure components that make up the Microsoft Azure platform. When it comes to moving SQL Server systems into the Azure platform having a solid understanding of the Azure infrastructure will make migrations successful and making support solutions much easier.

Designing your Azure infrastructure properly from the beginning is extremely important. An improperly designed and configured infrastructure will provide performance problems, manageability problems, and can be difficult to resolve without downtime.

As Azure scales around the world many more companies, no matter where they are located, will begin moving services from on-premises data centers into the Azure Cloud, and a solid foundation is the key to successful migrations.

With four new regions announced in Europe, bringing the total of European regions up to 12, more and more companies will be looking at the cloud for the hosting needs. Seating for this day-long session is limited, so you’ll want to register right away to ensure you get a seat at the session.


March 19, 2018  4:00 PM

Denny Cherry & Associates Consulting has two VMware vExperts

Denny Cherry Denny Cherry Profile: Denny Cherry

VMware recently announced they’re vExpert list for 2018 and I’m proud to say that both Joey and myself were on the VMware list for 2018. The VMware vExpert program is designed to recognize those in the VMware community who help out with the VMware community at large. While the vExpert list looks rather large, it’s a big world and there’s a lot of people working around the world helping VMware users to setup various VMware products. I know that both Joey and myself and thrilled to have been awarded this award for 2018.


March 12, 2018  4:00 PM

I want VMs in Azure to be members of my on-premises domain. How do I do this?

Denny Cherry Denny Cherry Profile: Denny Cherry
Azure, Virtual Machines

Having VMs in Azure which are members of your on-premises domain is a pretty important part of your Cloud implementation.  There’s a couple of ways to do this, but I’ll be covering what we at DCAC think is the best option.  In basic terms, you’ll set up a VPN from the Azure vNet to your on-premises network.  From there you’ll want to add domain controllers to Azure which are members of the on-premises domain (not just another domain with the same name). Then change your vNet to use those DCs as your DNS servers, reboot your other VMs, and you’ll be able to add the other VMs to your Active Directory domain.  Here are some details:

The first step is to put some domain controllers in Azure.  To do this, you’ll need a site to site VPN between Azure and your on-premises environment.  If you have multiple on-premises sites, then you’ll want to create a VPN between Azure and all your on-premises environments.  If your A zure environment is hosted in multiple regions, then you’ll want to create a mesh network when each on-premises site in VPNed into all of your vNets.  You’ll probably also want your vNets VPNed to each other (Peering of your networks between sites may be an option as well depending on how you’ve set things up).  If you have an extremely large number of users at your site, then Express Route might be something worth looking into instead of a site to site VPN.


Once the Site to Site VPN (or Express Route) then you can focus on putting some domain controllers in Azure.  Each site within your Azure environment should have at least 2 DCs, and they should be created within an Availability Set, or an Availability Zone (depending on what your standard is going to be for setting these up).  You can now set the vNet to use the office DCs as DNS Servers. Once that’s done, reboot the Azure VMs that you want to make domain controllers and promote them to DCs.  When making them DCs, you’ll probably want them to be a fairly large VM size so that the promotion process doesn’t take that long. You can resize them later.  Once the VMs in Azure have been created as DCs, you’ll want to make those VMs have static IP addresses (whatever IPs they have are fine).  Make a note of these IPs as you’ll need to enter them in a second.

Once the DCs are setup go into the vNet configuration and set the DNS servers for the vNet and change the vNet to use the new Azure DCs as your DNS Servers (you wrote these down at the end of the prior paragraph).  Then reboot any VMs that you’ve created already in the vNet.

At this point all the VMs that you have already created before now can be added to the domain without issue just like any other machine in your environment.


March 5, 2018  4:00 PM

What should MAXDOP be set to?

Denny Cherry Denny Cherry Profile: Denny Cherry


A lot of the examples you’ll see for MAXDOP on the web assume a large server with multiple physical sockets and multiple NUMA nodes.  But if you have a smaller server, like a lot of us do these days, what should you set the MAXDOP to?

The basic rules still apply, that you should set the MAXDOP to 1/2 of the size of your NUMA node. Just because you’re running a smaller server doesn’t mean that you don’t have NUMA configured, it just means that you have a single NUMA node.  So for example if you have a server with one socket and six cores, then your MAXDOP should probably be set to 3; since three is 1/2 the size of the server.

Now there’s a lot of it-depends that goes with this, but this gives you a starting point. You might need to decrease MAXDOP to 2 and see how this affects the server.

Keep in mind that making changes to MAXDOP during the business day isn’t recommended as making changes to MAXDOP will flush the plan cache and cause all the queries to be recompiled.


February 26, 2018  4:00 PM

Can I Use Azure Threat Detection On-Premesis?

Denny Cherry Denny Cherry Profile: Denny Cherry
Locked Bike


The short answer here is no.  The threat detection features that you see in Azure are not available in the on-premises product. This includes VMs running SQL Server instances in Azure.  The only way to get the SQL Server threat detection features that Azure offers is going to be to use the SQL DB feature in Azure.



February 19, 2018  4:00 PM

VMs in Azure region can’t talk to MySQL database service in same region

Denny Cherry Denny Cherry Profile: Denny Cherry

I ran into an interesting issue last week. I had VMs in the US West region of Azure which was unable to talk to the MySQL database service (PaaS) also in US West. The problem is turned out was due to a new feature that needed some adjusting to make work (there’s already a bug open to get this fixed).

The issue was that I couldn’t log into the MySQL PaaS service using VMs in my vNet. The error that I was getting was that I couldn’t access the PaaS service using VMs within a vNet.

The underlying issue was that the configuration of the Subnet within the vNet had the Microsoft.Sql service endpoint configured for that subnet.  Once that was removed from the Subnet I was able to connect from the VMs to the MySQL for SQL Databases Service.

Microsoft is thankfully already aware of this problem.  If you are using any combination of the PaaS services SQL Server, MySQL, Postgres and you want to use the Microsoft.Sql service Endpoints; for now, you need to put any virtual machines connecting to them of different subnets. Those subnets can be within the same vNet; they just need to be within different subnets within your vNet configuration.

In my case, my servers are only using MySQL and nothing within the subnet is trying to connect to SQL DB or SQL DW, so removing the Service End Point was the easiest solution.  Once I did this, I was able to access my web servers again without issue.


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