A Weird Networking Problem with Azure SQL Database (and Fios)

Published On: 2020-04-20By:

Note: This is my first blog post in a while. You too may have been stressed by recent events in world. I’m also doing a large content project I’ll hope you get to enjoy in the near future too. This post actually ties into working from home.



So anyway, one of our customers recently spun up a new Azure SQL Database in the Azure South Africa North region, and two of their team members couldn’t connect to it from their homes. The common element–both of them used Verizon Fios as their ISP.

It’s important to note that connectivity for Azure SQL Database is to a public IP address. Each region has a public IP address and a lookup takes place, and then you are connected through a gateway and you eventually connect to the database. The IP address is just a public endpoint. If I run a trace route to a database running in the Azure US East region I see:

Josephs-MacBook-Pro-3:Dropbox joey$ traceroute dcac-demo.database.windows.net
traceroute to cr4.eastus2-a.control.database.windows.net (, 64 hops max, 52 byte packets
1 ( 2.224 ms 2.849 ms 1.953 ms
2 ( 12.961 ms 12.978 ms 14.438 ms
3 ( 10.461 ms 9.803 ms 8.983 ms
4 ( 16.069 ms 6.967 ms 12.133 ms
5 ( 11.460 ms 15.657 ms 11.314 ms
6 be-201-ar03.ivyland.pa.panjde.comcast.net ( 14.815 ms 13.470 ms 13.775 ms
7 be-33287-cr01.newark.nj.ibone.comcast.net ( 18.519 ms 17.500 ms 19.012 ms
8 be-1301-cs03.newark.nj.ibone.comcast.net ( 16.457 ms 23.452 ms 20.628 ms
9 be-2303-pe03.newark.nj.ibone.comcast.net ( 15.248 ms 21.317 ms 22.250 ms
10 ( 16.467 ms 18.986 ms 23.555 ms
11 ae23-0.ear01.ewr30.ntwk.msn.net ( 24.966 ms 22.497 ms
ae24-0.ear01.nyc30.ntwk.msn.net ( 26.774 ms
12 be-21-0.ibr02.ewr30.ntwk.msn.net ( 32.792 ms
be-20-0.ibr01.nyc30.ntwk.msn.net ( 27.437 ms
be-20-0.ibr01.ewr30.ntwk.msn.net ( 34.036 ms

You can see that on steps 7-9 it my connection jumps onto the Comcast backbone (ibone.comcast.net) network, and at step 11 jumps onto the Microsoft Azure network (msn.net). I truncated the output of the trace route there.

Monica Rathbun (b|t ) who works with me at DCAC, also had Fios and was able to help us troubleshoot this. When Monica ran a trace route to the public IP address the  of Azure SQL Database in South Africa North it looked like:

C:\Users\monica>Tracert egpaftz.database.windows.net

Tracing route to cr1.southafricanorth1-a.control.database.windows.net []

over a maximum of 30 hops:

  1    <1 ms     1 ms    <1 ms  Fios_Quantum_Gateway.fios-router.home []

  2     3 ms     1 ms     2 ms

That is not how the internet is supposed to work. While we tried to figure out how to get in touch with someone at Verizon to fix this, which through normal consumer channels is not fun. So while we waited for that to get fixed, we had another options to fix this.

Introducing Private Link

Azure Private Link was recently introduced as generally available for Azure SQL Database and allows for you to have a truly private connection to your database. For several years now you have been able to use network endpoints to allow a specific VM or App Service to connect to Azure SQL, however that design had some limitations. The first being that it still routed the connection to the database over the public IP address. The second was that network endpoints did not support multi-region scenarios. With Private Link your database has it’s own private IP address on the virtual network where it is deployed.

In our client’s case, this work around involved connecting to an Azure VPN in US East which would then be connected to South Africa North. One interesting thing about Private Link is that it doesn’t support Azure Virtual Network peering, so you will need to create a Gateway if you want your traffic to traverse virtual networks. Additionally, we were working in two different subcriptions, which mean we had to use the PowerShell from here. Private Link is easy to configure from your Azure SQL server logical server, but be sure you have the right permissions in Azure RBAC. I needed to be granted the network contributor role in order to get the GUI to work.

The Conclusion

I had some issues that were permissions related which delayed our implementation of Private Link, and I was fortunate enough to have some members of the Azure Networking product group helping me out. Since Microsoft and Verizon are technically partners (Verizon is an ExpressRoute partner) they were able to get in touch with some folks as at Verizon, and they were able to resolve the problem. Sort of–the trace routes still look weird, but everyone can connect. Verizon reports that the trace routes from what they can see look normal. Which tells me they are doing something really weird on the router itself with how Azure traffic is routed.

Photo by Pixabay on Pexels.com




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Storage Field Day 19 MinIO #SFD19

Published On: 2020-02-27By:

In January I had the chance to attend Storage Field Day 19 in Santa Clara, where we got to meet with a wide variety of startups and large enterprise storage companies. One of the more interesting companies we meet with was MinIO which has a really interesting and compelling object-based storage product.

Some of MinIOs Customers and Use Cases

I’ve talked about object storage here before, but it’s a very different paradigm than the traditional block based storage you may currently be using. With block storage files are split into evenly sized blocks of data (typically somewhere between 64 KB and 1 MB depending on your vendor). Data protection is provided by traditional RAID options.

Object storage on the other hand doesn’t split files into blocks. Files are stored as objects which contain the file data, metadata, and a unique identifier. There is no limit on the size or amount of the metadata associated with the file. If you have ever created a managed disk in Azure, taken a backup to URL, or used an Azure SQL Database you’ve used object based storage. In object based storage, redundancy is generally provided by maintaining three copies of the object (e.g. a write isn’t considered complete until it writes to all three copies).

Object storage is designed to solve problems of scale. One of the things I learned at Comcast was that the cost of SAN storage didn’t scale to some of the massive petabyte scale data problems we had. The management overhead, the cost, and sometimes even the storage itself does not scale. This is a problem largely for companies like Microsoft, Amazon, Google, Facebook, etc, who have massive amounts of data to store.  But as data volumes grow there are lots of other firms who have very large volumes that they need to manage.

MinIO is a firm that offers such a solution. MinIO offers open source storage management software that offers extremely fast (183 GB/s reads and 171 GB/s writes). It is fully compatible with Amazon’s S3 API, which has somewhat become the de facto standard for object storage. They were working on Azure Blob Storage support when we visited.

One of the ways MinIO is able to get such good performance out of pretty standard hardware is by taking advantage of SIMD processor instructions, which all more text and number crunching to be performed per CPU instruction which dramatically increases performance. SQL Server uses this through the query processor’s use of batch mode.

MinIO’s storage can also be used as a persistent store for Kubernetes (drink), or used for systems like Spark, TensorFlow, and a replacement for Hadoop HDFS. Where you would probably use this in your environment would be to replace your file servers, or as a target for container storage, or maybe even an analytic store. Or you want to become a cloud storage provider and you need to host 50 PB of data in your data center.

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Storage Field Day 19–Western Digital #SFD19

Published On: 2020-02-03By:

As I mentioned in my post last week I recently had the opportunity to attend Storage Field Day 19, where I got to meet with a wide variety of storage software and hardware companies in Silicon Valley. One of the more interesting companies we met with was a longtime player in storage—Western Digital. (Disclosure—I own shares of Western Digital and was gifted an SSD after the event) One of the overwhelming themes of the week was the vast amounts of data that we are generating much of which is coming from video and IoT device telemetry. Western Digital estimates that 103 zetabytes (that’s 103MM petabytes, or 103 Billion terabytes) of just IoT data will be created by 2023.


We were able to hear from a wide array of executives at Western Digital making up various parts of their business. There are a few market forces that are driving the direction of the company. The first area is gaming—building internal NVME drives with up to 2 terabytes with bandwidth up to 3480 MB/second. Performance is one aspect of gaming systems, but design aesthetic and cooling are also very important.  PC Gaming is a $37.5 billion market, so Western Digital sees this as a major market for them.

While the gaming part of the presentation focused on bleeding edge performance, the rest of the afternoon looked at increasing storage densities. While it went unsaid, I feel like much of the development in the hardware business is increasingly focused on public cloud providers like Microsoft and Amazon, as well as large scale data companies like Facebook and Twitter. Western Digital is at the forefront of this development through the develpment of zoned storage. One of the goals of this extension to the NVME standard is to  allow ultra-fast SSDs to be zoned similar to the way hard drives can now. This is not technology that you will be implementing in your data center anytime soon, however it will likely be coming to a cloud provider in the near future.

The other aspect of storage futures are increased densities. While many analysts have prematurely speculated about the death of the spinning hard drive (in lieu of lighter, faster, cooler solid-state drives), the density offered by traditional hard drives is unmatched. Western Digital showcased volumes up to 20 TB, as well as multi-actuator driveswhich can increase the performance of a spinning disk by an order of magnitude. These drives will consume more power than a traditional drive, but less than the two traditional drives. The data on these platters is striped in a RAID-0 fashion on the drive itself.


The world is heavily dependent on reliable, fast storage for all of the data systems modern life demands. As one of the leading builders of storage media, Western Digital is well positioned to support both end users and hyperscale cloud providers now, and in the future.

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Storage Field Day 19–Current State of the Storage Industry #SFD19

Published On: 2020-01-28By:

Last week I got to spend some time meeting with numerous storage companies in Silicon Valley. I along with another dozen or so delegates met with companies large and small, including Western Digital, Dell EMC, NetApp, and startups like MinIO. I’ll be writing posts in coming weeks to talk about some of the interesting technology we learned about this week.


Photo by Anthony on Pexels.com

In this post I wanted to focus on some interesting scenarios. It’s something I specifically noticed when we were at Western Digital but came up again particularly with the startups we met with. I had this thought, and then on Sunday Argenis Fernandez (b|t) who recently returned to Pure Storage about about after this tweet.


Argenis was complaining about file systems because when you have very fast (think NVME, or faster) storage, or storage-class memory the overhead of all the things the file systems does become a significant portion of the time that it takes to complete an I/O operation. This isn’t significant when your IOs take 4-5 milliseconds to complete, but when they are completing in 50 microseconds you notice the time it takes for the filesystem to timestamp a file.

This leads me to the point I wanted to make in the post. Storage technology futures are very much bifurcated (that’s a fancy word for going in two directions) –on one end there is ultra-high performance NVME storage for workloads like gaming and ultra-high throughput trading systems. On the other end there is a lot of development around ultra-high density storage for hyperscale providers (that’s basically your public clouds and Facebook).

Did you know that there were hard drives with multiple actuators (needles to a record player for those of you who are old)?

Multi Actuator Technology: A New Performance Breakthrough

The reason why this is happening is that spinning hard drives are here to stay, for density reasons (you may have heard that the world is going to have eleventy billion zetabytes by 2022 and most of it will be in cloud, or something to that effect),  and SSDs still lack the density required to say be a cloud provider or host most of the world’s photos.

The cloud providers are also part of the high-speed storage game–mostly to be able to do things like NMVE over fabric, which will allow ultra-fast disk to by virtualized and shared.

What does this mean for you as a data professional and consumer of storage? It means things probably aren’t going to change that much for you. If you are working with an all-flash vendor for performance storage, you’ll see the gains as NVME rolls in, but a lot of the ultra-high speed storage will be limited by the rest of stack (OS and RDBMS). If you are in the public cloud, I think you will see storage get gradually faster and less latent over the next 18 months, and you will see densities increase in hard drives. Your SAN admin will get some better tools, that I’m going to talk about in some coming posts.






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