Scalability

IoT Hub vs Event Hub–A quick comparison

December 11, 2016 Azure, Cloud Computing, Cloud to Device, Communication Protocols, Connectivity, Contrained Networks/Devices, Data Hubs, Device Shadow, Device to Cloud, Device Twin, Emerging Technologies, Event Hubs, HTTP2, Identity of Things (IDoT), Intelligent Cloud, Internet of Things, Interoperability, IoT, IoT Hub, IoT Privacy, IoT Security, Messaging, Microsoft, Performance, Protocols, Reliability, Scalability, Tech-Trends No comments

With this article I am trying to provide you a birds eye view comparison of IoT Hub and Azure Event Hub, so that some of you may stop feeling that there is nothing new in IoT Hub.

For the interest of this article, I put together a table with side-by-side comparison of some important features/desired features from an IoT Hub like platform.

Feature IoT Hub Event Hub
Communication Supports both device-to-cloud and cloud-to-device bidirectional communication Supports only device-to-cloud communication
State Management Can maintain device state using Device Twins and query them whenever needed. Not Supported
Protocol Support AMQP 1.1, AMQP over Web Sockets, MQTT 3.2, MQTT over Web Sockets, HTTP 1.1, Web Sockets. AMQP 1.1, AMQP over Web Sockets, HTTP 11 , Web Sockets only
Protocol Extensions Provides IoT protocol gateway a customizable implementation for industrial protocol channelling. Not Supported
Security Provides identity to each device and easily revocable through IoT Hub Device Management portal. Shared access policies with limited revocation capabilities are provided.
Monitoring/ Operations Provides a rich set of features through Device Management capability. Includes individually enable/disable or provision new device. Change security keys as needed. View/identify individual device problems easily. Does not provide individual performance metrics. Can provide only a high level aggregated metrics only.
Scalability Scalable to thousands/millions of simultaneous devices Limited number of simultaneous connections up to 5000 connections per Azure Service Bus Quotas. Event Hub provides a capability to partition your message to channel it in to associated Service Bus quotas.
SDK Support/ Developer Support Provides very good Integration SDK and developer support. Both Azure IoT  Device SDK and IoT Gateway SDK are the most essential kits provided for almost all devices/OS platforms. It also support all the latest programming languages such as C#, Node.js, Java and Python.
Also provides  direct MQTT, AMQP and REST based HTTP APIs.
Very detail oriented documentation provided.
.NET, Java and C apart from protocols such as AMQP, HTTP API interfaces.
Files/Images Upload Capability Supports IoT devices/solutions to upload files/images/snapshots to cloud and define a workflow for processing them. Not Available
Message Routing Very decent message routing capability is available out of the box. Up to 10 end points can be defined and Advanced Rules can be defined on how routing should occur. Requires additional programming and hosting to support as per the need.

From this comparison table, you can analyse that IoTHub is the right candidate for your IoT solution needs, as Event Hub lacking certain capabilities that are essential for an IoT Ingestion point. If you are only requiring to send messages to cloud and doesn’t require any fancy stuff as IoTHub provides, you can choose Event Hub.

Remember with more power comes more responsibility, that’s what IotHub intend to provide to you.

Hope this overview was helpful. Please feel free to comment or initiate a discussion any time. Please share your feedbacks on this article as well.

Scalability – Scale Out/In vs Scale Up/Down (Horizontal Scaling vs Vertical Scaling)

October 1, 2016 Architecture, Azure, Cloud Computing, Cloud Services, Horizontal Scaling, Performance, Reliability, Resilliancy, Scalability, Scale Down, Scale In, Scale Out, Scale Up, Software/System Design, Vertical Scaling, Virtualization No comments

When you work with Cloud Computing or normal Scalable highly available applications you would normally hear two terminologies called Scale Out and Scale Up or often called as Horizontal Scaling and Vertical Scaling.  I thought about covering basics and provide more clarity for developers and IT specialists.

What is Scalability?

Scalability is the capability of a system, network, or process to handle a growing amount of work, or its potential to be enlarged to accommodate that growth. For example, a system is considered scalable if it is capable of increasing its total output under an increased load when resources (typically hardware) are added.

A system whose performance improves after adding hardware, proportionally to the capacity added, is said to be a scalable system.

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This will be applicable or any system such as :

  1. Commercial websites or Web application who have a larger user group and growing frequently,
  2. or An immediate need to serve a high number of users for some high profile event or campaign.
  3. or A streaming event that would need immediate  processing capabilities to serve streaming to larger set of users across certain region or  globally.
  4. or A immediate work processing or data processing that requires higher compute requirements that usual for a certain job.

Scalability can be measured in various dimensions, such as:

  • Administrative scalability: The ability for an increasing number of organizations or users to easily share a single distributed system.
  • Functional scalability: The ability to enhance the system by adding new functionality at minimal effort.
  • Geographic scalability: The ability to maintain performance, usefulness, or usability regardless of expansion from concentration in a local area to a more distributed geographic pattern.
  • Load scalability: The ability for a distributed system to easily expand and contract its resource pool to accommodate heavier or lighter loads or number of inputs. Alternatively, the ease with which a system or component can be modified, added, or removed, to accommodate changing load.
  • Generation scalability: The ability of a system to scale up by using new generations of components. Thereby, heterogeneous scalability is the ability to use the components from different vendors.

Scale-Out/In / Horizontal Scaling:

To scale horizontally (or scale out/in) means to add more nodes to (or remove nodes from) a system, such as adding a new computer to a distributed software application.

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Pros:

  • Load is distributed to multiple servers
  • Even if one server goes down, there are servers to handle the requests or load.
  • You can add up more servers or reduce depending on the usage patterns or load.
  • Perfect for highly available web application or batch processing operations.

Cons:

  • You would need additional hardware /servers to support. This would increase increase infrastructure and maintenance costs.
  • You would need to purchase additional licenses for OS or required licensed software’s.

Scale-Up/Down/Vertical Scaling:

To scale vertically (or scale up/down) means to add resources to (or remove resources from) a single node in a system, typically involving the addition of CPUs or memory to a single computer.

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Pros

  • Possibility to increase CPU/RAM/Storage virtually or physically.
  • Single system can serve all your data/work processing needs with additional hardware upgrade being done.
  • Minimal cost for upgrade

Cons

  • When you are physically or virtually maxed out with limit, you do not have any other options.
  • A crash could cause outages to your business processing jobs.

We discussed in detail about the both approach in Scalability, depending on the need you will have to choose right approach. Nowadays high availability of cloud computing platforms like Amazon AWS/Microsoft Azure etc., you have lots of flexible ways to Scale-Out or Scale-Up on a Cloud environment, which provides you with virtually unlimited resources, provided you are being capable to pay off accordingly.

Hope this information was helpful, please leave your comments accordingly if you find any discrepancies or you have any queries.