real-time push notifications using hybrid cloud · 2020-06-11 · now that you know about push...

REAL-TIME PUSH NOTIFICATIONS USING HYBRID CLOUD

Aneesh PulukkulAssociate Principal EngineerEMC

2015 EMC Proven Professional Knowledge Sharing 2

Table of Contents

Introduction to Business Model .................................................................................................. 3

What are Push Notifications? ..................................................................................................... 4

Hybrid cloud Primer ................................................................................................................... 5

Hybrid Cloud in Action......................................................................................................... 7

Solution Overview ...................................................................................................................... 8

High Level Flow – How does it work? ..................................................................................... 8

Scalability – How does it support millions of devices? ...............................................................12

Reliability – Is your solution fault tolerant? ................................................................................14

Vendor-supplied features (built-in for platform) ......................................................................14

Design for failure in solution ..................................................................................................14

Data storage – How does Flash Memory Storage help? ...........................................................15

Performance ..........................................................................................................................15

Capacity ................................................................................................................................16

Data Protection and Availability .................................................................................................16

Deployment Model ....................................................................................................................17

Conclusion ................................................................................................................................18

Appendix – List of terms ............................................................................................................19

References ...............................................................................................................................21

Footnotes ..................................................................................................................................22

Disclaimer: The views, processes or methodologies published in this article are those of the

author. They do not necessarily reflect EMC Corporation’s views, processes or methodologies.


Introduction to Business Model

To understand the model better, consider a couple of scenarios applicable in our day-to-day life:

A soccer game is being played between your favorite teams and you do not want to miss

watching the match. However, at the same time, an urgent work matter needs your

attention. As the game progresses, you receive score updates sent as notifications to

your mobile device. You feel lucky, don’t you?

You are a smartphone techie who uses a mobile app to get updates on the current

events happening in your city.

Now imagine that you are starting a business (bitten by entrepreneur bug!) that creates

interesting mobile applications for the aforementioned scenarios. As you may have inferred from

the scenarios above, a key requirement of the applications is that they need to receive

notifications for a range of purposes.

Once you are ready with the business plan, you decide to develop a platform using technical

resources to achieve this business functionality. At that point, you realize that it is a time-

consuming and costly affair to set up a platform that can support the functionality of sending

millions of notifications. This is where a custom notification service on hybrid cloud becomes

important. It saves time and money by eliminating steps such as procuring and configuring

hardware and software resources, hiring a team to address non-functional business

requirements, and setting up a service team to maintain infrastructure. Sounds promising,

doesn’t it?

Here is the set of features the custom notification service platform offers:

Comprehensive Notification Service as Platform as a Service (PaaS1) to send

notification messages to mobile applications.

Web interface to perform administrative tasks configuration activities.

Multi-tenant model to support many vendors.

Secured REST (Representational State Transfer) API (Application Programming

Interface) endpoints that can be used by vendor’s application development team.

High performance computing and data storage to provide a close to real-time

experience.

Data protection and availability features.


Ever wondered how to design such solutions that send notifications to millions of users? Is

cloud computing a good choice for such solutions? How can market leaders like EMC and

Microsoft help you build such solutions with industry-leading technologies?

This Knowledge Sharing article answers these questions by covering the basics of push

notifications, hybrid cloud, and a design approach for building the notification service. An

overview of technology products from market leaders is provided that will enable you to address

the challenges and solve problems you may face during the design phase.

What are Push Notifications?

Have you ever wondered how messages and application updates are received on your mobile?

Push Notification Services (PNS) are hosted services through which notifications are sent to

target devices. The benefit of push notifications is that applications in the device need not

constantly pull for updates or messages. There are different implementations of PNS hosted by

various technology firms.

For example, consider Microsoft Push Notification Service (MPNS)2. MPNS enables sending

notifications to Windows Phone devices after an initial registration process. This is achieved by

creating a device-specific Uniform Resource Identifier (URI) and storing it in the MPNS

database. The URI could be time-bound and can be renewed when it expires. Anyone who

wants to send notifications can make use of this device URI once the device shares it. Refer to

Figure 1 for a better understanding of the push notification flow,

Note: Security for cloud and data storage is a vast topic and is outside the scope of this

article.


Hybrid cloud Primer

Now that you know about push notifications, the next concept that you need to understand,

before moving on to the solution overview is the hybrid cloud. The cloud paradigm has been

around for a few years and is already implemented by technology companies like Microsoft,

EMC, Amazon, and Google. Whenever you hear the buzzword cloud, it’s likely that you will hear

other buzzwords like public cloud, private cloud, and hybrid cloud. Have you ever thought about

the difference between these three and how they matter? To keep things simple, here is a short

explanation of these three cloud models3:

Public Cloud: In this model, the compute, network, and storage services are available for use

over the Internet. Two examples of public cloud are Amazon Web Services and Microsoft Azure.

Here, the ownership of infrastructure is taken up by cloud vendors.

Private Cloud: In this model, the enterprise takes ownership since the compute, network, and

storage services are within a firewall of an on-premises data center, meaning that these are not

available on a public network such as the Internet.

Figure 1: Push Notifications Flow


Hybrid Cloud: In this model, services of the public cloud and private cloud are used in

conjunction.

Here is an example that will helpful for understanding hybrid cloud:

Microsoft Azure is a public cloud that runs across Microsoft managed data centers across

different regions around the globe. Azure Services provides you with Virtual Machines (VM)

to host a website that captures data from users and to host a worker process that performs

batch processing – essentially, your compute resources are on public cloud. Meanwhile,

you’re also using EMC products for data storage which are set up at your enterprise’s on-

premises data center – meaning your data storage is on private cloud.

Now that you have one of the services – VMs – on public cloud and another – data storage

– on private cloud, all you need now is to establish a secure connection between the public

cloud and the private cloud to enable an integration of these components. Microsoft Azure

provides features such as ExpressRoute1 and Virtual Network1 to achieve this. While

ExpressRoute uses dedicated carrier partners, Virtual Network is designed based on the

concept of Virtual Private Network (VPN). Both features have the same goal of enabling a

secure link between data centers in the public and private cloud using industry-standard

protocols. Once connectivity is established, applications hosted on hybrid cloud are ready to

go! Refer to Figure 2 for the hybrid cloud model example.


Hybrid Cloud in Action

Figure 2: An example of the hybrid cloud model

Note: All hybrid cloud architectures need not follow the compute-on-public cloud and

storage-on-private cloud architecture. There are hybrid cloud architectures that have both

compute and storage resources on public cloud as well as private cloud.


Solution Overview

High Level Flow – How does it work?

The custom push notification service is designed to run on a hybrid cloud with Microsoft Azure

being the public cloud vendor and a company using EMC products as the private cloud vendor.

Refer to Figure 3 for a high level view of the solution.

Figure 3: High Level Flow

The interaction of application vendor(s) and notification service hosted on hybrid cloud is

summarized below:

1. Vendor registers application with the service – This step stores the vendor details

into service database.

2. Vendor sends notifications to service.

3. Service validates the source based on the credentials created during registration

process.

4. Service sends a message to the endpoint specified by the device URI – This is

received by the MPNS server.

5. MPNS forwards the notification to the appropriate device.


The interaction between mobile application(s) and push notification service hosted on hybrid

cloud is summarized below:

At this point, you may be wondering about internal workings of the solution. How does it accept

requests from vendors? How does it perform registration and delivery of notifications? Figure 4

shows a low-level solution architecture to address your questions by bringing clarity about

components working under the hood.

Figure 4: Solution Architecture at low level

1. Mobile application establishes a channel with MPNS.

2. MPNS returns URI (unique per device).

3. Application sends URI along with the device details to service in order to register the

mobile device with service. In this step, the service stores the device details –

including the URI – in the database.


The solution is designed primarily using four major components:

1. a REST service

2. a worker process Registration Processor

3. a worker process Notification Dispatcher

4. data storage

Also the solution makes use of queue structure to hold the requests received through REST

service. This is a conscious decision made to avoid a heavy load on the REST service

considering a scenario where millions of devices and vendors are registering with the service. In

such cases, millions of notifications have to be sent to the devices. Let’s address questions that

typically arise when you view the architecture diagram.

How does the REST service help the Application Vendor and Mobile Apps?

The REST service provides the following API for Application Vendors:

Register – This is consumed by a Vendor Registration web interface that helps vendors

do a self-registration process. The registration is approved by a service administrator

after which approval-intimation will be sent to vendors. If the vendor wishes to stop the

service, this endpoint can be used to deregister from the service database by passing

required details. Vendor-specific secret keys are generated during registration approval

and the vendor can view them from the web interface.

Send Notification - Application vendors can consume this REST endpoint using a

desktop application or web application, or even a mobile application to send a

notification to mobile apps. The REST service validates the incoming requests from

application vendors using the secret key generated during the registration approval

process.

As for mobile devices, there is a REST endpoint to register the device with service. Typically,

when a user downloads and installs the app on a mobile device, it asks the user to complete the

registration process. During registration, in the background, it establishes connection with

MPNS and receives the device-specific URI. On completion of device registration with custom

push notification service, the service database will have details of the device including the

device URI sent from MPNS.


What is the role of the Registration Processor? Why are Registration Processor

and Notification Dispatcher running on different machines?

Registration Processor is implemented as a background worker process that continuously polls

the Registration Queue which holds the registration requests from devices and application

vendors. The processing logic of registration request is segregated from the web server that

hosts the REST API. This makes the REST API lightweight and offloads the heavy processing

workload to the worker process.

Notification Dispatcher, implemented as a worker process, needs to poll Notification Queue at

regular intervals, and for each notification it needs to fetch details of devices from data storage.

For each device, it needs to dispatch the notification to MPNS using the device URI.

Is it required to build the queue data structure or is it available in the cloud

platform?

Most cloud vendors provide queue as a built-in feature in their cloud platform. Microsoft Azure

provides built-in queues as part of a component named Service Bus4. Service Bus queues have

features such as ordered delivery that guarantee delivery order in a sequence batch delivery

that helps process multiple items in a batch and certain advanced features which are outside

the scope of this article.

You may wonder why there is no mention of cloud in terms of computing resources regarding

our solution design discussion. All the virtual machines you see in the architecture are running

on cloud and the beauty of this approach is the flexibility to increase or decrease the number of

virtual machines based on the workload. This is further explained in the scalability section of this

article.

Note: In the Introduction to Business Model section, there is a mention of the web interface

that helps perform administrative tasks and configuration activities. That web application

can be hosted on the same VM where REST service is hosted (details on the web interface

design are not covered in this article). Since the solution follows a PaaS service model, the

web interface is a standard functionality, and therefore mentioned in the feature set.


Scalability – How does it support millions of devices?

What is the most interesting aspect of cloud computing? Consider a scenario where your

solution needs to use hundreds of virtual machines for peak hours, suppose two hours per day.

The on-premises approach requires that you buy hundreds of machines and keep them with

you. Does that sound profitable? Not really. It consumes a lot of real estate and incurs

maintenance charges.

With cloud, you just need to address a large scale workload by increasing the number of virtual

machines either manually or in an automated fashion, referred to as scaling-out. Cloud vendors

expose Service Management API5 for scaling purposes. This feature is referred to as dynamic-

scaling or auto-scaling and is often closely associated with the term, elasticity. The important

point to note is that you just need to pay for the number of hours you use the virtual machine.

Scale out vs. Scale up

Scaling-out (also called horizontal-scaling) means you increase the number of virtual

machines with same configuration; scaling-up (also called vertical-scaling) means you

upgrade the virtual machine with a higher configuration.

Consider a traffic controller solution under normal workload that uses 4 VMs, each having 2

Central Processing Unit (CPU) cores and 4 GB Random Access Memory (RAM) to operate.

To accommodate workload during rush hours:

- Scale-out approach increases the VM count by 4, meaning that there are total 4

VMs to level the workload. The newly added VMs have the same configuration as

existing VMs.

- Scale-up approach replaces each VM with higher configuration having 4 CPU cores

per machine and 6 GB of RAM.

A calculation of cost for hardware configuration makes it clear that the scale-out approach

would be cost-effective for hardware resources. When you use VMs provided by platforms

such as Microsoft Azure, you do not need to purchase the license for Windows Server

Operating System – you just pay for the number of hours the VMs are in use.


How do we decide whether to increase the number of virtual machines for unpredictable and predictable workloads?

For unpredictable workloads, this is easily achieved by using the Performance Counters feature

in the Windows Operating System. Performance counters help you capture certain operating

parameters such as CPU use, memory use, request per seconds received by web server, etc.

You can choose any of the pre-existing performance counters that provide information on

processor use, memory use, or even add custom performance counters that provide metrics on

pending items in the queue. Data captured by performance counters can be used to increase

the number of virtual machines. As when increasing the number of VMs, it very important to

decrease the number of VMs once the workload comes down. Remember, in cloud you pay for

the allocated machines regardless of whether they are running or idle. To automate the scaling

process, you need to incorporate a rule engine that works based on the pre-defined rules.

Examples on rules for unpredictable workload:

The approach above addresses unpredictable workloads.

If you know the workload increase rate at certain time periods, i.e. predictable workloads, the

rules could be framed as:

Now that you have an understanding of the particulars of scaling, the next question is how to

test the dynamic scaling. Unlike unit testing (test individual components) or integration testing

(test integrated components), performance testing (also called load testing) has certain

challenges. You will need to generate large number of requests to the REST service hosted on

cloud to mimic a scenario where thousands of application vendors are simultaneously sending

notifications. A plethora of commercial tools are available for load testing, but you can use a free

and simple performance testing tool from Microsoft, Web Capacity Analysis Tool (WCAT)6.

WCAT can simulate scenarios where thousands of concurrent users send requests to the REST

service.

Increase VM count for REST Service by 2 if CPU usage exceeds 75%.

Increase VM count for Notification Dispatcher by 1 if number of pending items in

Notification Queue exceeds 10K.

Increase VM count for REST Service by 10 between 10AM and 12PM every day.

Increase VM count for Notification Dispatcher by 20 between 10AM and 12PM every day.


Reliability – Is your solution fault tolerant?

When building a real-time notification solution, reliability is a critical feature that impacts the

business significantly. Imagine what could happen when VMs that deliver notifications go down

for some reason. Users will not receive important notifications and consequently they will stop

using your service which results in a huge dip in the revenue. Therefore, the solution should use

fault-tolerant features provided by vendors and any additional mechanism built by the service

development team.

Here are some approaches:

Vendor-supplied features (built-in for platform)

Failover Instances

Microsoft Azure provides a Service Level Agreement (SLA)7 of at least 99.95% availability of

virtual machines if the solution is deployed on two or more virtual machine instances. This

means that, when a machine goes down, it will redirect all requests to the second instance so

that downtime is avoided. The placement of these two instances will be chosen by Azure in

such a way that both do not fall under the same point or region of failure.

Auto-recovery on failure

Microsoft Azure is equipped with agents that continuously monitor each VM allocated for

consumers, sending signals to the VM and using a heartbeat check to confirm whether the VM

is running in a healthy state. When a VM goes down, the agent loses the heartbeat signal from

the VM and takes the necessary steps to restart the VM.

Design for failure in solution

Cloud-based systems have higher complexity due to the large number of interconnected

components and a resource pool that is shared by millions

of users and applications. This could cause issues in your

solution that is hosted on the cloud. Though cloud platform

provides features such as failover and auto-recovery,

failures and crashes that occur in your solution need to be

addressed by an approach called Design for Failure8. This approach dictates that the solution

should be designed to anticipate failures and account for these failures, meaning that it should

handle the failures gracefully.

If anything can go wrong, it will.

- Murphy’s Law


Logging and tracing

The concept of logging and tracing is not new. However, in a cloud-based system, it gains

importance since troubleshooting and debugging is relatively more complex in cloud

environments than in traditional systems. A fully-fledged logging and tracing system needs to be

implemented in the application in order to capture all issues that can directly or indirectly lead to

system failure. It is recommended to store log data in a separate storage area other than

solutions data. This helps prevent performance impact to main applications that may be caused

by a huge amount of log data.

Alert Mechanism

Certain areas are critical to your application and these areas need to be placed under a

monitoring procedure that helps to identify issues that occur and instantaneously send alerts to

a team of administrators. This proactive approach needs to be implemented in order to address

issues that cannot be resolved by the solution itself. These days, many applications are

designed to have self-healing capabilities as well as an alert mechanism that require attention

and manual action.

Data storage – How does Flash Memory Storage help?

What are the considerations for choosing data storage? The most important are performance

and capacity.

Performance

As you may have inferred from the title of this article, notifications need to be in real-time. Thus,

latency plays a big role here, as it negatively impacts performance. Suppose you’ve chosen

Microsoft SQL Server9 as your database for storing details of vendor, devices, and notification

history. SQL Server’s latency heavily depends on the underlying storage system. Traditional

storage systems with spinning hard disk arrays have certain inherent latency issues caused by

mechanical motion. This is where storage leaders like EMC help with all-flash array10

-based

storage systems such as XtremIO®11. Latency rates for Input/Output (I/O) operations are

considerably low and best suited for storing and retrieving data for real-time applications. Flash

arrays do not have the aforementioned latency issues that are suffered by rotational storage

devices like hard disk array.


Capacity

Another important consideration for data storage is capacity. Imagine storing details about

millions of devices and the details about the notifications sent to them. Over time, it could reach

a scale of terabytes (TB) or even petabytes (PB). With this amount of data, you cannot go very

far without considering a storage system designed to support massive storage scale.

XtremIO is built with a scale-out design that provides not only higher performance but also large

capacity by forming clusters of multiple storage units called X-Bricks12

. The clusters have better

performance and scalability (easily scales to petabytes) than all other arrays and do not

compromise availability.

Data Protection and Availability

Choosing XtremIO as a storage system is a wise decision. Once you have sorted out the design

concerns about data storage, the next challenge is how to protect your data. Will you be able to

afford data loss for millions of devices and thousands of application vendors? Of course not!

As for compute and network resources you have seen that Microsoft Azure offers the SLA and

availability features with the platform. As a business continuity plan, we need to make sure that

a similar availability feature is planned and implemented for data storage in the event of failure

of a site or individual storage array. EMC offers an industry leading data protection and

availability technologies VPLEX®13 and RecoverPoint

14. While VPLEX is designed to address

availability, RecoverPoint is built for continuous data protection by replicating data. VPLEX, in

conjunction with RecoverPoint, can be configured to ensure a zero recovery time objective

(RTO) and a near-zero recovery point objective (RPO). XtremIO is fully integrated with VPLEX

and RecoverPoint, addressing application data protection and availability concerns.


Deployment Model

When the solution is targeted for global users, the best deployment model is multi-site

deployment. In this model, the solution will be deployed in multiple sites across the globe. The

advantage of this model is:

Low Latency and high performance

Serves users from closest location and thus avoids latency during communication. One

key component to rescue us here is Microsoft Azure Traffic Manager15. It helps you

configure a single and global web address for accessing the deployed solution and

internally redirects to the solution that is hosted at the closest location.

High Availability and Disaster Recovery

Each site can be synchronized with each other, greatly contributing to High Availability

and Disaster Recovery. For example, if the solution is deployed on data centers across

USA, Europe, and Asia, one of the sites will be given a primary role and the other two

become secondary. When one of the sites is down due to a disaster and cannot be

brought back without impacting business, one of the secondary sites can be made

primary. This approach needs to be implemented at two levels:

1. At the public cloud end where the REST service is hosted. For implementing

such failover-to-secondary-site, Microsoft Azure Traffic Manager is available to

help us again. In addition to performance policy that identifies closest

deployment, it has a failover policy that helps to detect the health of primary and

fails over to secondary in case issues or downtime is detected for primary.

2. At the private cloud end where storage systems reside. To ensure storage

system availability, we can make use of VPLEX which is designed to provide

benefits of a multi-site deployment model. It offers a deployment model – VPLEX

Geo – which is built based on the multi-site deployment concept. The VPLEX

Geo model along with RecoverPoint helps enable asynchronous replication and

data movement between storage arrays hosted in data centers over large

distances.


Conclusion

This article discussed the right ingredients for a real-time and scalable push notification service

and attempted to convey that effective implementation of such a service for mobile devices and

application vendors is not a complex task once we understand concepts and address the design

concerns. We gained an understanding of how push notifications work by an example of MPNS.

We discussed how a hybrid cloud model can take the best of both public and private worlds. We

examined how the hybrid cloud model undoubtedly helps us optimize business by reducing

CapEx for infrastructure such as compute, network, and storage and eliminating development-

cost of features such as fault tolerance and auto-scaling of resources.

The solution overview helped in understanding high level and low level components along with

non-functional requirements such as the scalability and reliability. We walked through important

considerations such as performance and capacity when choosing a data storage system and

learned why a flash array-based storage system such as XtremIO is the right fit for a high

performing real-time application. We discussed the importance of data protection and availability

and got to know the options such as VPLEX and RecoverPoint. Finally, we saw the multi-site

deployment model solution and how components like Azure Traffic Manager, and VPLEX helps

us address availability and disaster recovery challenges. Now that you have seen the advanced

technologies on cloud computing and data storage, let us conclude the article with a quote by

sci-fi writer and futurist Sir Arthur C. Clarke.

Any sufficiently advanced technology is indistinguishable from magic.


Appendix – List of terms

API Application Programming Interface. It specifies the functionalities

provided by a software application and how to make use of these

functionalities while programming. API documentation is supplied to

software application developers who consume routines provided by

the application.

Multi-tenancy A design-approach where a single instance of a software solution

addresses multiple tenants. The tenant could be an individual user or

customer who shares the software component.

Performance Counter Performance Counters in Windows Operating system helps capture

and provide data that is related to the performance of the operating

system or applications. It’s an effective way to fine-tune the operating

system and dynamically add or remove resources to address the

performance bottleneck.

Queue A First In, First Out (FIFO) data structure used to hold data elements

in an ordered manner. This data structure is built on the real-world

concept of queues where the first person entered in a queue will be

served first.

Recovery Point

Objective

Represents an amount of data loss in terms of time period that is

acceptable to business.

Recovery Time

Objective

A point in time to which the system will recover. The time duration

allowed to recover from a failure.

Reliability An application is said to be reliable when it works as expected for a

given amount of time without failure. Reliability is also synonymously

used with the term fault-tolerance.


REST Representational State Transfer. An architectural style where

resources are read or written using a stateless protocol such as

Hypertext Transfer Protocol (HTTP). This style is mostly used for

exposing web-based services in networked applications.

Scalability Scalability of an application is a quantified measurement of user base.

If an application supports 10 million users without compromising

performance and availability, the application is scalable for 10 million.

If application becomes unavailable when more than 10 million users

access it, 10 million is termed as the scalability limit for the

application.

Storage Array A storage array is a data storage system that contains multiple disk

drives and a cache memory. Source:

http://www.techopedia.com/definition/1009/disk-array

Uniform Resource

Identifier(URI)

Identifies the name of a resource by use of a textual format and

provides a way to represent the resource in a network such as

internet. The textual format comprises protocol, web address, and

resource details.

Virtual Machine(VM) A virtual machine is a logical machine created on top of a physical

machine using a hypervisor, a virtualization software component.

Hypervisor enables a VM to make use of hardware resources of the

physical machine where it runs.

Virtual Private Network Virtual Private Network (VPN) is a logical network that enables

connectivity to a private network using a public network such as

Internet. Tools and systems that implement VPN have security and

encryption features to authorize users who are connecting to a private

network.


References

1. Enabling Hybrid Cloud Today with Microsoft Technologies Whitepaper

http://www.microsoft.com/en-us/download/details.aspx?id=39052

2. Building a Trusted Cloud: Deployment Strategies for Private and Hybrid Clouds

http://www.emc.com/collateral/emc-perspective/h8558-cloud-trust-ep.pdf

3. How to use Azure Service Bus Queues

http://azure.microsoft.com/en-in/documentation/articles/service-bus-dotnet-how-to-use-

queues/

4. Microsoft Azure ExpressRoute Technical Overview

http://msdn.microsoft.com/en-us/library/azure/dn606309.aspx

5. Microsoft Azure Virtual Network Overview

http://msdn.microsoft.com/en-us/library/azure/jj156007.aspx

6. Introduction to EMC XtremIO storage array

http://www.emc.com/collateral/white-papers/h11752-intro-to-XtremIO-array-wp.pdf

7. EMC XtremIO for Microsoft SQL Server

http://www.emc.com/collateral/white-papers/h13163-xtremio-microsoft-sql-server-wp.pdf

8. EMC RecoverPoint Specification-sheet

http://www.emc.com/collateral/software/specification-sheet/h2770-recoverpoint-ss.pdf

9. Configure Failover Load Balancing using Microsoft Azure Traffic Manager

http://msdn.microsoft.com/en-us/library/azure/hh744832.aspx

10. EMC VPLEX Geo Specification Sheet

http://india.emc.com/collateral/hardware/specification-sheet/h8690-vplex-geo-ss.pdf

http://www.microsoft.com/en-us/download/details.aspx?id=39052

http://www.emc.com/collateral/emc-perspective/h8558-cloud-trust-ep.pdf

http://azure.microsoft.com/en-in/documentation/articles/service-bus-dotnet-how-to-use-queues/

http://azure.microsoft.com/en-in/documentation/articles/service-bus-dotnet-how-to-use-queues/

http://msdn.microsoft.com/en-us/library/azure/dn606309.aspx

http://msdn.microsoft.com/en-us/library/azure/jj156007.aspx

http://www.emc.com/collateral/white-papers/h11752-intro-to-XtremIO-array-wp.pdf

http://www.emc.com/collateral/white-papers/h13163-xtremio-microsoft-sql-server-wp.pdf

http://www.emc.com/collateral/software/specification-sheet/h2770-recoverpoint-ss.pdf


http://india.emc.com/collateral/hardware/specification-sheet/h8690-vplex-geo-ss.pdf


Footnotes

1 http://www.microsoft.com/industry/government/guides/cloud_computing/5-PaaS.aspx

2 http://msdn.microsoft.com/en-us/library/windows/apps/ff402558(v=vs.105).aspx

3 http://www.cloud-competence-center.com/understanding/cloud-computing-deployment-models/

4 http://azure.microsoft.com/en-in/documentation/articles/fundamentals-service-bus-hybrid-solutions/

5 http://msdn.microsoft.com/library/azure/ee460799.aspx

6 http://www.galcho.com/articles/StressTestingWCAT.aspx

7 http://azure.microsoft.com/en-in/support/legal/sla/

8 http://www.asp.net/aspnet/overview/developing-apps-with-windows-azure/building-real-world-cloud-

apps-with-windows-azure/design-to-survive-failures 9 http://en.wikipedia.org/wiki/Microsoft_SQL_Server

10

http://searchsolidstatestorage.techtarget.com/definition/Flash-array 11

https://store.emc.com/in/Product-Family/EMC-XtremIO-Products/EMC-XtremIO-All-Flash-Scale-Out-Array/p/EMC-XtremIO-Flash-Scale-Out 12

http://www.xtremio.com/x-brick 13

http://www.emc.com/storage/vplex/vplex.htm 14

http://www.emc.com/storage/recoverpoint/recoverpoint.htm 15


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Use, copying, and distribution of any EMC software described in this publication requires an

applicable software license.

http://www.microsoft.com/industry/government/guides/cloud_computing/5-PaaS.aspx

http://msdn.microsoft.com/en-us/library/windows/apps/ff402558(v=vs.105).aspx

http://www.cloud-competence-center.com/understanding/cloud-computing-deployment-models/

http://azure.microsoft.com/en-in/documentation/articles/fundamentals-service-bus-hybrid-solutions/

http://msdn.microsoft.com/library/azure/ee460799.aspx

http://www.galcho.com/articles/StressTestingWCAT.aspx

http://azure.microsoft.com/en-in/support/legal/sla/

http://www.asp.net/aspnet/overview/developing-apps-with-windows-azure/building-real-world-cloud-apps-with-windows-azure/design-to-survive-failures

http://www.asp.net/aspnet/overview/developing-apps-with-windows-azure/building-real-world-cloud-apps-with-windows-azure/design-to-survive-failures

http://en.wikipedia.org/wiki/Microsoft_SQL_Server

http://searchsolidstatestorage.techtarget.com/definition/Flash-array

https://store.emc.com/in/Product-Family/EMC-XtremIO-Products/EMC-XtremIO-All-Flash-Scale-Out-Array/p/EMC-XtremIO-Flash-Scale-Out

https://store.emc.com/in/Product-Family/EMC-XtremIO-Products/EMC-XtremIO-All-Flash-Scale-Out-Array/p/EMC-XtremIO-Flash-Scale-Out

http://www.xtremio.com/x-brick

http://www.emc.com/storage/vplex/vplex.htm

http://www.emc.com/storage/recoverpoint/recoverpoint.htm


real-time push notifications using hybrid cloud · 2020-06-11 · now that you know about push...

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