Understanding Storage Accounts in Azure

General-purpose Storage Accounts

A general-purpose storage account gives you access to Azure Storage services such as Tables, Queues, Files, Blobs and Azure virtual machine disks under a single account. This type of storage account has two performance tiers:

• A standard storage performance tier which allows you to store Tables, Queues, Files, Blobs and Azure virtual machine disks.
• A premium storage performance tier which currently only supports Azure virtual machine disks. See Premium Storage: High-Performance Storage for Azure Virtual Machine Workloads for an in-depth overview of Premium storage.

Blob Storage Accounts

A Blob storage account is a specialized storage account for storing your unstructured data as blobs (objects) in Azure Storage. Blob storage accounts are similar to your existing general-purpose storage accounts and share all the great durability, availability, scalability, and performance features that you use today including 100% API consistency for block blobs and append blobs. For applications requiring only block or append blob storage, we recommend using Blob storage accounts.

Note:

Blob storage accounts support only block and append blobs, and not page blobs.

Blob storage accounts expose the Access Tier attribute which can be specified during account creation and modified later as needed. There are two types of access tiers that can be specified based on your data access pattern:

• A Hot access tier which indicates that the objects in the storage account will be more frequently accessed. This allows you to store data at a lower access cost.
• A Cool access tier which indicates that the objects in the storage account will be less frequently accessed. This allows you to store data at a lower data storage cost.

If there is a change in the usage pattern of your data, you can also switch between these access tiers at any time. Changing the access tier may result in additional charges. Please seePricing and billing for Blob storage accounts for more details.

For more details on Blob storage accounts, see Azure Blob Storage: Cool and Hot tiers.

Before you can create a storage account, you must have an Azure subscription, which is a plan that gives you access to a variety of Azure services. You can get started with Azure with a free account. Once you decide to purchase a subscription plan, you can choose from a variety ofpurchase options. If you’re an MSDN subscriber, you get free monthly credits that you can use with Azure services, including Azure Storage. See Azure Storage Pricing for information on volume pricing.

To learn how to create a storage account, see Create a storage account for more details. You can create up to 100 uniquely named storage accounts with a single subscription. See Azure Storage Scalability and Performance Targets for details about storage account limits.

Storage account billing

You are billed for Azure Storage usage based on your storage account. Storage costs are based on the following factors: region/location, account type, storage capacity, replication scheme, storage transactions, and data egress.

• Region refers to the geographical region in which your account is based.
• Account type refers to whether you are using a general-purpose storage account or a Blob storage account. With a Blob storage account, the access tier also determines the billing model for the account.
• Storage capacity refers to how much of your storage account allotment you are using to store data.
• Replication determines how many copies of your data are maintained at one time, and in what locations.
• Transactions refer to all read and write operations to Azure Storage.
• Data egress refers to data transferred out of an Azure region. When the data in your storage account is accessed by an application that is not running in the same region, you are charged for data egress. (For Azure services, you can take steps to group your data and services in the same data centers to reduce or eliminate data egress charges.)

Understanding Caching

Understanding Caching

Caching Approach

Characteristics

Advantages

Disadvantages

Comments

Caching Services

Out of Process

In Memory

Distributed

Accessible by all types of Azure technologies. Scalable.

Extra cost for Service

For building high-performance, scalable cloud systems.

Azure In-Role Caching

Out of Process

In Memory

Distributed

Can run in the memory space of existing Roles

Only available to Web/Worker Roles within Cloud Services.

Suitable for adaptation to existing applications migrated to Azure.

ASP.NET/IIS Cache

In-Process

In Memory

Single-Locale

Runs in the memory space of the existing application.

Requires cache synchronization to work with scalable Azure applications.

Will require adaptations to use distributed caching when used with Azure load balancing.

Azure SQL Database

Out of Process

Out of Memory

Distributed

Data is persistently stored in a database table.

Requires custom coding to serialize data, and for management such as expiration.

Slower than in-memory applications, may be throttled in periods of high request.

Azure Table Storage

Out of Process

Out of Memory

Distributed

Data is persistently stored in Azure table storage.

High performance for very large datasets, cost-effective. Requires custom code.

Slower than in-memory, but faster than SQL. May be throttled in periods of high requests.

Azure Blob Storage

Out of Process

Out of Memory

Distributed

Data is persistently stored in Azure Blob storage.

Can leverage geo-redundant persistent storage. Requires custom code.

Slower than in memory, but easy to make highly distributed.

ASP.NET Azure Session State in Azure

ASP.NET Azure Session State in Azure

In addition to the data caching, we can also use Windows Azure Caching as the storage mechanism for ASP.NET Session State and ASP.NET Page Output Caching. The Session State Provider for Windows Azure Caching and the Output Cache Provider for Windows Azure Caching are the out-of-process storage for ASP.NET applications which will greatly work with Windows Azure load balancers. To use Windows Azure Caching as the storage mechanism for ASP.NET Session State and ASP.NET Page Output Caching, first you need to configure Cache Cluster (using one of the two approaches explained above) and then you need to configure your ASP.NET application to use the Windows Azure Caching. After you have configured the Cache Cluster, you can use Windows Azure Caching for ASP.NET Session State and ASP.NET Page Output Caching by adding necessary configuration setting in the web.config file.

The following configuration setting in the web.config allows to use the Session State Provider for Windows Azure Caching for web applications.

  
              type="Microsoft.Web.DistributedCache.DistributedCacheSessionStateStoreProvider, Microsoft.Web.DistributedCache"
          cacheName="default"
          useBlobMode="true"
          dataCacheClientName="default" />
  

The cacheName specifies the name of the Cache used for persisting Session State data.

The following configuration setting in the web.config configures the Session State Provider for Windows Azure Caching for web applications

  
    
                     type="Microsoft.Web.DistributedCache.DistributedCacheOutputCacheProvider, Microsoft.Web.DistributedCache"
            cacheName="default"
            dataCacheClientName="default" />
    
  

Programming Azure Cache

Programming Azure Cache

Programming with Windows Azure Caching

In order to work with Windows Azure Caching from client apps, you need to add the following namespace in your client app:

using Microsoft.ApplicationServer.Caching;

To programmatically access the Windows Azure Caching, you first need to create an instance of DataCache class.

The following code block will create a cache client by creating an instance of DataCache which will take the settings from configuration file.

//Creating a cache object
DataCacheFactory cacheFactory = new DataCacheFactory();
DataCache dataCache = cacheFactory.GetDefaultCache();

The above code block will create the cache client object by using DataCacheFactory object. The GetDefaultCache method of DataCacheFactory object will return the DataCache object.

Adding and Retrieving Data from the Windows Azure Cache

To add an item to Cache object, we can use either Add or Put method of DataCache object. The Add method adds an object to the Cache object with a specified key and will generate an exception if the item is already exists with the same key. The put method adds the object to the Cache object with a specified key if the key does not exist, and replaces if the key is already exists.

The following code block adds the collection of data objects to Cache:

//Query from DB and adding data to Cache 
var categories = categoryRepository.GetAll();
dataCache.Add("categories", categories);

In the above code block, querying data from Database and adding this data to Cache object with a key name “categories” and we can take the data from Cache for the subsequent requests for the same data which can avoid database round trips and improve the performance of the application.

Using the overloads of the Add and Put methods of DataCache object, we can override the timeout interval, which are specified in the Cache Roles settings.

The following code block adds the data to the Cache with time span that allows to specify when the object should expired from Cache.

dataCache.Add("categories", categories, TimeSpan.FromMinutes(45));

The above code block adds the data to the Cache object with a key categories and specified the timeout as 45 minutes.

The following code block retrieves the data from Cache:

//Getting the Cache item with key "categories"
IEnumerable category = dataCache.Get("categories") as IEnumerable;

The Get method of the DataCache object retrieves the data from Cache where you have to give the key as the parameter value for the Get method. The above code block retrieves the data and casting it for the appropriate data type.

Working with a Cache Provider Class

In the previous steps, we have discussed how to perform data caching with Windows Azure Caching. Let’s create a Cache provider class that will help us better manage Data in the cache. Let’s create a contract type for the Cache provider.

public interface ICacheProvider
{
    object Get(string key);
    void Add(string key, object data);
    void Put(string key, object data);
    void Add(string key, object data, TimeSpan? timeout);
    void Put(string key, object data, TimeSpan? timeout);
    bool IsSet(string key);
    void Remove(string key);
}

The Get method returns the cached item based on the given key and Add and Put methods adds and puts an item into Cache. The IsSet method will return true if an item added on the Cache. The Remove method will remove an item from the Cache.

Let’s create a concrete implementation for the ICacheProvider. The below AzureCacheProvider Class is an implementation of ICacheProvider for Windows Azure Caching.

public class  AzureCacheProvider : ICacheProvider
{
private DataCache dataCache=null;
public AzureCacheProvider()
{
    //Creating a cache object by using DataCacheFactory
    DataCacheFactory cacheFactory = new DataCacheFactory();
     dataCache = cacheFactory.GetDefaultCache();
}
//Get cached item
public object Get(string key)
{
   return dataCache.Get(key);
}
public void Add(string key, object data)
{
    Add(key, data, null);
}       
public void Add(string key, object data, TimeSpan? timeout)
{
   //Add item to Cache
    if (timeout.HasValue)
    {
        dataCache.Add(key, data, timeout.Value);
    }
    else
    {
        dataCache.Add(key, data);
    }
}
public void Put(string key, object data)
{
    Put(key, data, null);
}
public void Put(string key, object data, TimeSpan? timeout)
{
    //Put item to Cache
    if (timeout.HasValue)
    {
        dataCache.Put(key, data, timeout.Value);
    }
    else
    {
        dataCache.Put(key, data);
    }
}
//Returns true if Cache item is exist
public bool IsSet(string key)
{            
    return (dataCache.Get(key) != null);
}
public void Remove(string key)
{
    dataCache.Remove(key);
}
}

In the below code block, we are using the ICacheProvider from an ASP.NET MVC application

private readonly ICacheProvider cache;
public CategoryController(ICategoryRepository categoryRepository,ICacheProvider cache)
{            
    this.categoryRepository = categoryRepository;
    this.cache = cache;
}      
public ActionResult Index()
{
    IEnumerable categories;
    var cachedCategories=cache.Get("categories");

    if (cachedCategories != null)
    {
        categories = cachedCategories as IEnumerable;
    }
    else
    {
        categories = categoryRepository.GetAll();
        cache.Put("categories", categories);
    }            
    return View(categories);
}      

In the Index action method, we are taking the data from Cache, if the cached item exists. If the item does not exist, we retrieve the data from Database and put it on Cache so that we can take the data from Cache for the subsequent requests. In this sample code, we are injecting an instance of AzureCacheProvider class through constructor for the contract type ICacheProvider.

Working with Cache in Azure

Working with Caching in Azure

Windows Azure Caching

Windows Azure is providing a caching service which can be used as a caching layer for your Cloud apps hosted on Windows Azure. Windows Azure Caching service is a highly scalable, distributed, in-memory Cache which allows developers to cache all data types, thus reducing the load on databases and improving the performance of the Windows Azure applications.

Using Windows Azure Caching, you can do the following:

• Cache data on Windows Azure Caching
• Use as storage mechanism for ASP.NET session state and ASP.NET page output caching

The new Windows Azure Caching allows you to deploy Cache on the virtual machines in which you have hosted your Windows Azure Cloud Services. Now you can cache on Web Roles and Worker Roles that can be easily scaled, managed and monitored just like your Cloud Services. You can also use the existing Windows Azure Shared Caching along with the new Caching option on the Cloud Services.

Cache Cluster

Cache Cluster is the Cloud Service role instance that you use for hosting your Cache. You can deploy the cache cluster in two different ways. You can deploy in a dedicated VM as well as you can share Caching with your Role instances.

The following are the two types of deployment options available for configuring cache.

· Co-located Role caching - The Cache shares the Virtual Machine resources with the Cloud Service application. In this option, you can share the resources of Web Role and Worker Role for Cache.

· Dedicated Role caching - The role instances dedicated only for your caching. In this way, you would be deploy the Cache in a dedicated VM by using a Cache Worker Role.

Configuring Co-located Role Cache Cluster

If you want to configure your cache along with your Role instances, you can choose the co-located Role cache cluster as the deployment option.

The following steps will configure the Windows Azure Role for using co-located Role Caching

1. In Visual-Studio, right-click on the Windows Azure Role, and click properties.

2. In the properties window, choose the 'Caching' tab.

3. In the Caching tab, check the 'Enable Caching (Preview Release)' checkbox.

4. Choose 'Co-located Role' for the Cache Cluster settings. By default, this will be 'Co-located Role' when we enable Caching.

5. Choose the percentage of Cache size. By default Cache size will be 30 percentage. This means that 30 percentage of VM memory allocated for Cache. You can change the Cache size whatever you want for your caching solution.

6. Configure the settings of Caches. We can specify the 'Time to Live (min)' for the time interval of Cache for expiry and 'Expiration Type' for specifying the expiration type of Cache object.

By default, value of “The Time to Live” would be 10 minutes and the Expiration Type would be Absolute. The Absolute expiration type is specifying that the timer for the expiration would be start after the data added into Cache object. If the expiration time is 10 minutes, the cache will be expire after 10 minutes when the item is added into Cache. The other expiration types are 'Sliding Window' and 'None'. If the Expiration Type is 'Sliding Window', the timer for the expiration time would be reset after each item is retrieved from the Cache. If expiration type is 'None', items in the cache will not be expired. In this scenario, you have to specify “Time to Live (min)” as 0.

Configuring Dedicated Role Cache Cluster

If you want to host your cache in a dedicated VM, you can choose the Dedicated Role cache cluster as the deployment option.

The following steps will configure the Dedicated Role cache cluster

1. Add Cache Worker Role project - To configure Dedicated Role cache cluster, you need to add a Cache Worker Role to your solution. Add a New Cache Worker Role project onto
your Windows Azure project.

When we are adding a new Cache Worker Role project, it will automatically enable Caching with Dedicated Role as the Cache cluster.

2. Configure the settings for Dedicated Cache Role - Right-click on the Cache Worker Role from the Windows Azure project, and click properties and choose Configuration

By default, the VM instance count would be 1 and Virtual Machine size would be small. You can change these setting based on your hosting plan for Dedicated Role Cache Cluster.

3. Configure the Cache settings for expiration time and expiration type.

Working with Cache Clients

In order to work with Windows Azure caching from Cloud Services applications, we need to install Windows Azure Caching client library onto your Web Role and Worker Role applications. The following steps will add a Windows Azure client library to a Web Role application. We can install the Windows Azure Caching client library by using NuGet.

From the following NuGet packages, Install Microsoft.WindowsAzure.Caching

The Windows Azure Caching NuGet package will install the necessary assmebly reference and will also add the configuartion setting on the configuaration file. You can also manually add the necessary assmeblies from the folder C:\Program Files\Microsoft SDKs\Windows Azure\.NET SDK\2012-06\ref\CachingPreview if you have installed Windows Azure SDK 1.7 on your system. At the time of this writing, Azure SDK 1.8 is the latest.

The Windows Azure Caching NuGet package will add a configuration element dataCacheClients into the web.config file.

The following configuration setting in the web.config file will configured a cache client for a web role application.

    
   

  
  
    
    
      
      
    
  

The identifier in the config settings specifies the name of the role that hosts the cache cluster

Working Azure App Fabrics

Working with Azure App Fabrics

Windows Azure AppFabric provides a comprehensive cloud middleware platform for developing, deploying and managing applications on the Windows Azure Platform.  It delivers additional developer productivity, adding in higher-level Platform-as-a-Service (PaaS) capabilities on top of the familiar Windows Azure application model.  It also enables bridging your existing applications to the cloud through secure connectivity across network and geographic boundaries, and by providinga consistent developmentmodelfor both Windows Azure and Windows Server.Finally, it makes development more productiveby providing a higher abstraction for building end-to-end applications,and simplifies management and maintenance of the application as it takes advantage of advances in the underlying hardware and software infrastructure.

There are three key components of Windows Azure AppFabric:

Middleware Services:platform capabilities as services, which raise the level of abstraction and reduce complexity of cloud development.

Composite Applications: a set of new innovative frameworks, tools and composition engine to easily assemble, deploy, and manage a composite application as a single logical entity

Scale-outapplication infrastructure:optimized for cloud-scale services and mid-tier components.

Following is a high-level overview of these Windows Azure AppFabric components and features.

Middleware Services

Windows Azure AppFabric provides pre-built, higher level middleware services thatraise the level of abstraction and reduce complexity of cloud development.  These services are open and interoperable across languages (.NET, Java, Ruby, PHP…) and give developers a powerful pre-built “class library" for next-gen cloud applications. Developers can use each of the services stand-alone, or combine services to provide a composite solution.

Service Bus(Commercially available now; updated CTP delivered October 2010)provides secure messaging and connectivity capabilities that enable building distributed and disconnected applications in the cloud, as well as hybrid applications across both on-premise and the cloud. It enables using various communication and messaging protocols and patterns, and removes the need for the developer to worry about delivery assurance, reliable messaging and scale.

Access Control (Commercially available now; updated CTP delivered August 2010)enables an easy way to provide identity and access control to web applications and services, while integrating with standards-based identity providers, including enterprise directories such as  Active Directory®, and web identities such as Windows Live ID, Google, Yahoo! and Facebook.

Caching (New CTP service delivered October 2010; commercially available in H1 CY11)accelerates performance of Windows Azure and SQL Azure based apps by providing a distributed, in-memory application cache, provided entirely as a service (no installation or management of instances, dynamically increase/decrease cache size as needed).  Pre-integration with ASP.NET enables easy acceleration of web applications without having to modify application code.

Integration(New CTP service coming in CY11) will provide common BizTalk Server integration capabilities (e.g. pipeline, transforms, adapters) on Windows Azure, using out-of-box integration patterns to accelerate and simplify development.  It will also deliver higher level business user enablement capabilities such as Business Activity Monitoring and Rules, as well as self-service trading partner community portal and provisioning of business-to-business pipelines.

Composite App(New CTP service coming in H1 CY11)will provide a multi-tenant, managed service which consumes the .NET based Composition Model definition and automates the deployment and management of the end to end application - eliminating manual steps needed by both developers and ITPros today.  It also executes application components to provide a high-performance runtime optimized for cloud-scale services and mid-tier components (automatically delivering scale out, availability, multi-tenancy and sandboxing of application components). Finally, it delivers a complete hosting environment for web services built using Windows Communication Foundation (including WCF Data Services and WCF RIA Services) and workflows built using Windows Workflow Foundation.

It’s a key characteristic of all AppFabric Middleware Services that they are consistently delivered as true multi-tenant services – you simply provision, configure, and use (no installation or management of machines/instances).

Composite Applications

AppFabric Composition Model & Visual Designer

As developers build next-generation applications in the cloud, they are increasingly assembling their application as a composite from many pre-built components and services (either developed in house or consumed from third parties cloud services).  Also, given that many cloud applications need to access critical on-premises business applications and data, there is a need to be able to compose from on-premises services easily and securely.  Finally, the highly distributed nature of these composite applications require more sophisticated deployment and management capabilities for managing all of the distributed elements that span the web, middle-tier and database tier.

Microsoft is advancing its Windows Azure AppFabric cloud middleware platform to provide a full composite application environment for developing, deploying and managing composite applications.  The AppFabric composition environment delivers three main benefits:

Composition Model A set of .NET Framework extensions for composing applications on the Windows Azure platform.  This builds on the familiar Azure Service Model concepts and adds new capabilities for describing and integrating the components of an application.  It also provides a consistent composition model for both Windows Azure and Windows Server.

Visual Design ExperienceA new Visual Studio based designer experience allows you assemble code from your existing application components, along with newer cloud services, and tie them together as a single logical entity.

Managed as a serviceThe Composite Application service is a multi-tenant, managed service which consumes the Composition Model definition and automates the deployment and management of the end to end application - eliminating manual steps needed by both developers and ITPros today.

The composite application environmentoffers the following benefits:

§  Greater developer productivity through rapid assembly, linking of components and automated deployment of the entire end-to-end application;

§  Easier configuration and control of entire application and individual components;

§  End-to-end application monitoring (events, state, health and performance SLAs);

§  Easier troubleshooting (through richer diagnostics and debugging of the whole application);

§  Performance optimization of the whole application (scale-out/in, fine-tuning, migration, etc);

§  Integrated operational reporting (usage, metering, billing).

Scale-out Application Infrastructure

Both the AppFabric Services and your own composite applications built using the Composition Model are built upon anadvanced,high-performance application infrastructure that has been optimized for cloud-scale services and mid-tier components.  The AppFabric Container provides base-level infrastructure such as automatically ensuring scale out, availability, multi-tenancy and sandboxing of your application components.The main capabilities provided by the AppFabric Container are:

Composition RuntimeThis manages the full lifecycle of an application component including loading, unloading, starting, and stopping of components. It also supports configurations like auto-start and on-demand activation of components.

Sandboxing and Multi-tenancy This enables high-density and multi-tenancyof the hosted components. The container captures and propagates the tenant context to all the application and middleware components.

State Management This provides data and persistence management for application components hosted in the container. 

Scale-out and High AvailabilityThe container provides scale-out by allowing application components to be cloned and automatically distributed; for stateful components, the container provides scale-out and high availability using partitioning and replication mechanisms. The AppFabric Container shares the partitioning and replication mechanisms of SQL Azure.

Dynamic Address Resolution and Routing In a fabric-based environment, components can be placed or reconfigured dynamically. The container automatically and efficiently routes requests to the target components and services.

Bridging On-Premises and Cloud

Finally, one of the important capabilities needed by businesses as they begin their journey to the cloud is being able to leverage existing on-premise LOB systems and to expose them selectively and securely into the cloud as web services. However, since most organizations are firewall protected, the on-premise LOB systems are typically not easily accessible to cloud applications running outside the organization’s firewall.

AppFabric Connect allows you to leverageyour existing LOB integration investments inWindows Azure using the Windows Azure AppFabric Service Bus, and Windows Server AppFabric.  This new set of simplified tooling extends BizTalk Server 2010 to help accelerate hybrid on/off premises composite application scenarios which we believe are critical for customers starting to develop hybrid applications.

(AppFabric Connect is available now as a free add-on for BizTalk Server 2010 to extend existing systems to both Windows Azure AppFabric and Windows Server AppFabric.)