Microsoft Ends AppFabric Support, NCache Keeps on Going!

April 2nd 2016 is proving to be an important date for Alachisoft’s product NCache. This is the date when Microsoft ends AppFabric support – essentially withdrawing the product from the market. See details on Microsoft AppFabric 1.1 for Windows Server Ends Support 4/2/2016

AppFabric was Microsoft’s answer to .NET industry’s need for an in-memory distributed cache to provide performance and scalability boost for .NET server applications. But, first it was late to the party with AppFabric 1.0 released in June 2010 (five years after NCache). And, second, it struggled to provide the features and functionalities considered de rigueur for in-memory distributed caches. Eventually, Microsoft decided to pull the plug on a product that essentially provided less features than other .NET caching solutions like NCache.

Read AppFabric vs NCache comparison and see for yourself how much AppFabric lacked in features and capabilities.

NCache is the most popular Open Source In-Memory Distributed Cache for .NET. It is available through GitHub or can be downloaded from our Alachisoft website. NCache is available for use either on-premises or in the Cloud (like Azure, Amazon, and others).

Interestingly, Microsoft’s proposed AppFabric replacement, Azure Redis Cache, is a cloud-based managed cache service. The on-premises version of Redis is not supported by Microsoft. And, you should also know that using Azure Redis Cache as a managed cache service means you lose all fine grained control over your cache and you are restricted to a simpler version of the client-side API.

On the other hand, NCache allows you to deploy it in Azure on a Virtual Machine as part of your infrastructure and gain full control over client-side and server-side code on an In-Memory Distributed Cache. You can also use the exact same version of NCache on-premises that you’re using in the Cloud. This way, you can start on-premises and later migrate to the Cloud without any code changes. Or, you can choose to have a hybrid of Cloud and on-premises application deployment. NCache works in all those scenarios seamlessly.

On top of all this, NCache provides a lot of powerful features and capabilities than even the on-premises Redis that has more features than Azure Redis Cache. Here is a detailed Redis vs NCache comparison.

We have several hundred satisfied name-brand customers using NCache for years, including customers in over 30 countries, dozens of industries and some of the biggest ecommerce and financial institutions on the planet.

So, if you want to replace AppFabric with a 100% native .NET distributed caching solution, try NCache. We are convinced that you will be impressed with its combination of powerful features and yet very simple and easy to use interface and tools. And, rest assured that NCache will be fully supported by Alachisoft including 24×7 support and you won’t be left hanging.

Fortunately, we’ve made it really easy for you to migrate from AppFabric to NCache. We’ve implemented an AppFabric Wrapper for NCache that allows you to keep your existing application code and migrate to NCache without any code changes (except changing namespaces). This takes all the risk out of the AppFabric-to-NCache migration.

NCache is industry’s oldest and most popular distributed cache. See some details on it.

NCache Details                  Edition Comparison                         Performance Benchmarks

Posted in ASP .NET performance, ASP.NET Cache, Distributed Cache | Tagged , | Leave a comment

How In-Memory NoSQL Improves .NET App Scalability?

Modern day .NET applications must be well equipped to cope with the scalability demands being put on them due to the explosion of ASP.NET web applications reaching millions of users, WCF web services applications handling Internet of Things (IoT) devices, and Big Data analytics applications processing huge amounts of data. Scalability here means to maintain the same high performance under extremely heavy loads that you see with no load.

The architectures of these .NET applications are very scalable because you can add more app servers as you need higher transaction loads. But, the problem is with data storage, especially relational databases like SQL Server and Oracle, and mainframe. Basically, data storage is unable to scale in the same manner as the application tier.

Some people propose that these .NET applications should stop using relational databases or mainframe and instead use NoSQL databases. But that is not possible in most cases because of business and legacy reasons. Relational databases also have various technical merits over NoSQL databases in how they’re able to handle the complexity of real world data.

Although, NoSQL databases don’t have the same scalability problems as relational databases, they can only be used for storing unstructured data and all structured data must still be kept in a relational database.

So, the bottom line is that NoSQL databases cannot completely replace relational databases. As a result, you still need to work with relational databases like SQL Server and Oracle whether you like or not and they have major scalability issues.

So, what is the answer to this problem? Well, the answer is to continue using relational database but with another type of NoSQL. And, this is called In-Memory NoSQL store. Although, the name sounds very similar to NoSQL databases, the In-Memory NoSQL is actually different. In-Memory NoSQL store is also called distributed cache or In-Memory Data Grid. NCache is a powerful In-Memory NoSQL store for .NET applications.

In-Memory NoSQL store does not persist any data on the disk for permanent storage. It keeps it in-memory and is therefore good only as a temporary store. As a result, it is not meant to replace relational databases that NoSQL databases claim to do. Instead, it is intended to be used “along with” relational databases and helps reduce pressure on them so they’re no longer a scalability bottleneck.

In-Memory NoSQL store like NCache can be used for caching data coming from relational databases so you can reduce database traffic that making them the bottleneck. It can also be used to store transient data (temporary data) created at runtime for a short period. One example of transient data is ASP.NET Session State storage in a load balanced web farm deployment.

In-Memory NoSQL store is linearly scalable in comparison to relational databases because it builds a dynamic cluster of In-Memory NoSQL storage servers and distributes all the data across these storage servers. And, you can easily add more servers at runtime without interrupting your applications as you need to handle a bigger transaction load.

In-Memory NoSQL Store
Figure 1: In-Memory NoSQL Store

Figure 1 shows you how an In-Memory NoSQL store like NCache is used by your application. NCache also synchronizes its store with relational databases to make sure the data in the In-Memory NoSQL store is always correct.

In most cases, your application uses a simple “cache API” to talk to the In-Memory NoSQL store and sees it as a cache. In other cases like ASP.NET Session State or ASP.NET View State caching, In-Memory NoSQL store usually has a pluggable module that plugs in directly without any code changes.

So, by using an In-Memory NoSQL store like NCache, your application can truly scale in a linear fashion and handle extreme transaction load. Now, whether you have web applications, web services applications, big data analytics applications, or other server applications with scalability needs, you are all set.

If you have a .NET application with scalability requirements, I recommend you take a look at NCache. Here are some useful links:

NCache Details          Edition Comparison              Quick Start Demo

Posted in NoSQL In-memory Datastore | Tagged , , , , | Leave a comment

How .NET Cache Improves Performance and Scalability?

Some of the very basic needs for .NET applications to stay competitive in today’s market are to be extremely responsive and scalable. The bottleneck in the way of achieving these benchmarks is your relational database.

This is a two fold bottleneck, first the reads from disk are very inefficient and time consuming. Secondly, you cannot scale out the database tier by adding more database servers. Whereas if you have a .NET distributed cache, it provides fast data access because it is in-memory and it can also scale linearly the same way your application tier does.

NCache is a .NET distributed cache that provides performance and scalability for your applications. It comes with a rich set of features including but not limited to cache elasticity, high availability, data replication, seamless integration with existing technologies and ease of management. Lets just focus on performance and scalability, as identified in the beginning. These are two fundamental metrics needed by .NET applications to survive in today’s world. Let’s see how NCache is positioned to cater for both.

NCache gets its performance edge over relational database because it keeps its data in memory and not on the disk. The performance boost over relational databases is ten times or higher depending on your hardware and .NET cache positioning in the network. For example if you deploy NCache as a local in-proc cache in your environment, the data access becomes lightning fast.

And the way NCache provides scalability is by allowing you to add more cache servers when your transaction load grows. So, if you see that your application getting overwhelmed by transaction load, just add a new cache server at run-time. You don’t even have to stop your application for this. With this new cache server added, you have the ability to serve more requests and all of this happens transparent to the user. Now, that’s what I mean by scalability.

ncache-architecture

 

There are a number of caching topologies that NCache offers to choose from depending on your specific need. The caching topology defines how your data is stored and the way individual cache servers in the cluster interact with one another. For example, Partitioned Cache, Partition-Replica Cache, Replicated Cache, and Mirrored Cache are the caching topologies.

If your primary concern with your .NET cache is scalability and not reliability you can use the ‘Partitioned Cache’ topology. On the other hand, if your primary focus is to get reliability and not scalability you should go for the ‘Replicated Cache’ topology. The ‘Partition-Replica Cache’ is the combination of both of these and gives you the best of both worlds. It provides you with reliability and scalability at the same time with some trade offs.

I would like to conclude by saying that if you want your application to be at par with the growing needs of performance and scalability, .NET distributed cache is the way to go.

Posted in .NET 4.0 Cache, ASP.NET Cache, Distributed Cache | Tagged , , | Leave a comment

Couchbase Alternatives Open Source Distributed Cache

The database tier based on traditional RDBMS has proven to be the biggest bottleneck in the way of achieving competitive response times for applications. This has forced the application vendors to look for alternatives that can provide improved performance. One such alternative is storing data in a distributed cache.

From the available cache technologies you need to pick one that answers most if not all of the major questions asked in this domain. Going forward I will be comparing two products in this arena, Couchbase and NCache – Open Source Distributed Cache.

1 – ASP.NET Sessions

ASP.NET Session State caching has come a long way starting from keeping the session information in-memory on the Web server (default), to having it on a State server, to storing it on a SQL server. All of these have one limitation in common and that is the Single Point of Failure. Session state is lost if any of the following happens: Web server goes down, the State server goes down or the SQL server goes down.

To answer all these concerns NCache provides a solution by saving session state in its Open Source Distributed Cache. Since it’s distributed there is no single point of failure. Despite its importance Couchbase does not support saving ASP.NET sessions.

2 – ASP.NET View State

ASP.NET uses View State to store pages, controls and custom values between multiple HTTP requests. In some cases where we have complex controls on a page e.g. Data Grid Control, the string representing the View State grows very large. In such a case you would be using extra bandwidth to pass this string back and forth without any real benefit, in addition you are opening up a loop hole with regards to security.

What are the ways to address these issues ? All we need to have is a distributed cache that can store the View State text and pass back an identifier that can be used to retrieve our View State from the store. NCache provides this exact functionality in form of ASP.NET View State Caching whereas Couchbase does not.

3 – Memcached Smart Wrapper

NCache provides support to integrate with Memcached in a transparent way using Memcached integration.

Let me just say a few words about Memcached, it is a popular distributed cache that is being used in the market but offers very basic caching features. It does not provide any support for high availability, data replication, cache elasticity, and ease of management.

Couchbase does not provide any such integration, so to be able to adapt to Couchbase for someone using Memcached there is only one way; Rewrite your code from scratch!

4 – Security & Encryption

One of the fundamental requirements of applications needing fast response times is that the data be secured. This makes security and encryption must haves for providers of distributed caching.

NCache is well equipped to provide support for both of these features in a comprehensive manner, Couchbase on the other hand fails to provide support for data encryption and active directory/ LDAP authentication. Read more on NCache encryption here.

5 – Read-through & Write-through

Read-through means that your application always asks the cache for data and the cache gets it from your data source if it doesn’t have it and caches this data for future accesses. This simplifies your application code greatly because cache API is very simple to use in comparison to the database.

Similarly write-through allows your application to write to the cache and the cache then writes the same data to the database either synchronously or asynchronously. Both these features facilitate you to have the cache as your enterprise data store and have all applications read from it and write to it.

NCache provides full support for both Read-through and Write-through but Couchbase fails to do so and hence lags behind NCache here as well. More on Read-through & Write through.

Further Reading

For feature by feature comparison of Couchbase with NCache please take a look at the following link:

Couchbase vs. NCache

Posted in Distributed Cache, Open Source Distributed Cache, Product Comparison | Tagged , , , | Leave a comment

AppFabric Alternatives Open Source Distributed Cache

Today’s applications need to scale and handle extreme data loads due to explosion of web technologies and Internet of Things. The biggest bottleneck in the way of achieving this is the data tier with relational databases. The need of the hour is to be able to make this data available to applications in a faster and more efficient way.

You can achieve this by using distributed caching of data that facilitates faster response times. There are a few big names in this domain with less than competitive products, e.g. Microsoft with their AppFabric caching product. In contrast to this NCache is an Open Source Distributed Cache that offers cutting edge technology and features.

An interesting point to note here is that Microsoft is no longer pushing AppFabric in their flagship cloud environment called Microsoft Azure. Instead, they’re recommending another Open Source cache called Redis (see NCache comparion with Redis). Why Microsoft chose to do so will become clearer as you read this article.

In the next few paragraphs, I’m taking a somewhat detailed look at some of the core differences between NCache and AppFabric.

1 – High Availability of Cache (Peer to Peer Architecture)

A distributed cache runs in your production environment and as part of your application deployment. Therefore, you should treat it just like a database when it comes to high availability requirements.

Any distributed cache that does not provide a peer to peer architecture for the cache cluster becomes very limiting. AppFabric does not provide such a clustering architecture and therefore is not as flexible as NCache for providing high availability. NCache provides a truly peer to peer clustering.

2 – Synchronization with Data Sources

A very core requirement of caching data is to keep it from getting stale. In plain simple words this means that the cache needs to refresh its data every time there is an update or remove operation in the master database. NCache provides a very strong mechanism to do this called “Data Synchronization” through three types of dependencies:

  •           SqlDependency (SQL Server 2005-2012 events)
  •           OracleDependency (Oracle events)
  •           Db Dependency (polling for OLEDB databases)

This is a feature that AppFabric lacks even though it is core to a powerful distributed cache.

3 – WAN Replication

As the name suggests, WAN replication deals with the availability of data in geographically dispersed data centers. NCache provides powerful WAN replication capability for its distributed cache in the following data center configurations:

  •        Active – Passive
  •        Active – Active

The first case is applicable to the situation where you want to have one data center to handle all user requests i.e. Active data center. And at the same time have a backup data center for disaster recovery, i.e. Passive data center. All the data operations on the active data center are replicated to the passive data center asynchronously. So that if the active DC goes down the passive will become active and start serving user requests.

The second case is applicable to the situation where you want to have two active data centers serving users in their nearby geographical area. Since both DCs are active, data would be getting replicated in both directions. So that if a need arises to reroute all traffic to one data center, in case one of the DCs is overwhelmed or goes down, it can be done without any data integrity issues.

AppFabric fails to provide this very much needed functionality at all levels.

4 – Search Cache with SQL

The real power of a cache lies in the fact that once it has the data, it should be made easily searchable and accessible. NCache comes with very handy tools to accomplish this task. Here they are:

  •        Object Query Language (OQL)
  •        Group-by for Queries
  •        Delete Statement in Queries
  •        LINQ Queries

AppFabric does not provide any of this and hence lacks behind NCache on this avenue as well.

5 – Memcached Smart Wrapper

NCache provides the ability to integrate with Memcached in a seamless way using Memcached integration.

For those of you not familiar with Memcached, it is a popular distributed cache that is being used in the market but offers very basic caching features. Does not provide any support for high availability, data replication, cache elasticity, and ease of management.

AppFabric does not provide any such integration, so to be able to adapt to AppFabric for someone using MemCached there is only one way; Rewrite your code from scratch!

6 – Cache Size Management – Priority Evictions

To be able to use memory available to the cache efficiently we have the concept of evictions. Simply put it means to remove relatively old data from the cache so that we may have space for newer items. There are a number of algorithms that NCache employs to carry out this important task, such as:

  •        Least Recently Used (LRU) Evictions
  •        Least Frequently Used (LFU) Evictions
  •        Priority Evictions
  •        Do Not Evict Option

Each of these options has its own advantages and disadvantages over others, with one being most suitable for a particular use case.  AppFabric only supports LRU evictions; this is a big limitation as some scenarios might demand to keep older data and to evict using some other matrix.

Further Reading

For feature by feature comparison of NCache with AppFabric please take a look at the following link:

AppFabric vs NCache

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Redis Alternatives Open Source Distributed Cache

The demand for high speed data access along with its integrity and fault tolerance is ever increasing in the contemporary application arena. Traditional disk based RDBMS systems have failed to answer these concerns in a comprehensive manner. This paved way for in-memory data solutions that cover all the bases listed above.

One such solution is Redis that has features to tackle many of the critical issues but falls short in some fundamental aspects. NCache is an Open Source Distributed Cache for .NET that answers these concerns effectively and also provides other additional features.

Here are some of the core differences between Redis and NCache.

1 – WAN Replication

First and the foremost Redis has no support for WAN replication of the cached data. The need for this feature becomes indispensable when your application is deployed in multiple data centers across the country or world. NCache provides powerful WAN replication capability for its distributed cache in the following data center configurations:

  •        Active – Passive
  •        Active – Active

The first situation is suitable when you have an active data center and a disaster recovery backup data center. The backup data center only becomes active if the active one goes down. And, for this to be possible, the distributed cache must be replicated to the passive data center so it is available when the data center becomes active.

The second situation is applicable where you have two active data centers serving geographically dispersed users so as to improve their access time. And, you want the ability to either reroute some of the traffic from one data center to another in case of overflow. Or, one of the data centers goes down and you want to route all its traffic to the other one.

In this second case, you need the distributed cache updates from both data centers to be replicated to the other ones and also handle conflict situations. This is the capability that NCache provides which Redis does not support.

2 – Security & Encryption

Many of the applications needing a distributed cache are dealing with sensitive and highly confidential data. Therefore, security and encryption are two areas that hold fundamental importance when talking about data storage and retrieval.

Redis is lacking support for both of these neither authentication nor encryption. NCache in contrast provides support for authentication and authorization through Active Directory / LDAP. NCache also provides very strong encryption options to encrypt the stored data. Here they are:

  •        3DES
  •        AES-128
  •        AES-192
  •        AES-256

Read more on NCache encryption here.

3 – Read-through & Write-through

Read-through and write-through are familiar concepts in the domain of distributed caching. But for people starting to get familiarized with caching it won’t hurt to give a brief definition for these.

Read-through means that your application always asks the cache for data and the cache gets it from your data source if it doesn’t have it. So, this simplifies your application code greatly because cache API is very simple to use in comparison to database.

Similarly write-through allows your application to write to the cache and the cache then writes the same data to the database either synchronously or asynchronously.

Both these features allow you to designate the distributed cache as your enterprise data store and have all applications read from it and write to it. And, the cache then deals with the database. This results in the cache always being synchronized with your database.

Despite its importance Redis lacks this feature but NCache covers it in length and breadth.

4 – Cache Administration

The effectiveness of distributed cache also depends on your ability to administer and monitor it through user friendly GUI tools. In this regard, Redis does not provide any GUI tools for its cache administration or monitoring. The only things available to you are the command line tools.

On the other hand, NCache provides powerful GUI based tools like NCache Manager and NCache Monitor for cache administration and monitoring. Some people however prefer to use command line tools because you can use them in scripts for automation. In this regard, NCache also provides all the cache administration through command line tools.

5 – ASP.NET View State Caching

View State is a powerful mechanism that ASP employs to store pages, controls and custom values between multiple HTTP requests across client and the server. This View State is passed in form of an encrypted text which becomes very large in cases involving forms with lot of controls, Data Grid control, or some other complex controls. This raises two concerns:

  •        Security risk
  •        Bandwidth usage

Both of these concerns will be answered if we have a distributed cache that can store the View State text and passes back an identifier that can be used to retrieve our View State from the store. NCache provides this exact functionality in the form of ASP.NET View State Caching whereas Redis does not.

6 – Memcached Smart Wrapper

Memcached is a popular distributed cache that is being used by a host of applications to benefit from the performance boost being discussed herein. It however has a number of limitations in the areas of high availability, data replication, cache elasticity, and ease of management.

The easiest way to address these issues for the customers using Memcached is to use NCache’s Memcached integration, such that the users can plug-in NCache to their existing Memcached applications without any code change. The users only need to change their application configuration files to take advantage of NCache’s distributed caching system.

Redis does not provide any such integration and hence falls behind on this as well.

Further Reading

For feature by feature comparison of NCache with Redis please take a look at the following link:

Redis vs. NCache

Posted in Open Source Distributed Cache, Product Comparison | Tagged , , , , , | 1 Comment

ASP.NET View State Caching in Microsoft Azure for Better Performance

ASP.NET View State is a client side state management mechanism, which is used to save page and control values. ASP.NET View State is a hidden field on the page as an encoded Base64 string. It is sent to client as part of every response and is returned to the server by the client as part of a post back.

[code lang=”csharp”]
<input id="__VIEWSTATE" type="hidden"
name="__VIEWSTATE" value="wEPDwUJNzg0MDMxMDA1D2QWAmYPZBYCZg9kFgQ
CQ9kFgICBQ9kFgJmD2QWAgIBDxYCHhNQcm2aW91c0NvbnRyb2xNb2RlCymIAU1pY3
Jvc29mdC5TaGFyZVBvaW50LldlYkNvbnRyb2xzLlNQQ29udHJbE1vZGUsIE1pY3Jv
29mdC5TaGFyZVBvaW50LCBWZXJzaW9uPTEyLjAuMC4wLCBDdWx0dXJlPW5ldXRyWw
sIFB1YmxpY0tleVRva2VuPTcxZTliY2UxMTFlOTQyOWMBZAIDD2QWDgIBD2QWBgUm
Z19lMzI3YTQwMF83ZDA1XzRlMjJfODM3Y19kOWQ1ZTc2YmY1M2IPD2RkZAUmZ18yN
DQ3NmI4YV8xY2FlXzRmYTVfOTkxNl8xYjIyZGYwNmMzZTQPZBYCZg8PZBYCHgVjbG
DQWBgUmZ19lMzI3YTQwMF83ZDA1XzRlMjJfODM3Y19kOWQ1ZTc2YmY1M2IPD2…."/>

[/code]

Problems with ASP.NET View State in Microsoft Azure

ASP.NET View State is a very important feature for applications deployed as web/worker roles in Microsoft Azure. But, View state comes with some issues that you need to understand and resolve in order to take full benefit from it.

First of all, ASP.NET View State becomes very large especially when your Microsoft Azure ASP.NET application has a lot of heavy controls on its pages. This results in heavy view state payload which travels back and forth between browser and your application on each request. Heavy view state payload slows down performance and also results in extra bandwidth consumption especially when an average ASP.NET View State ends up in 100’s of kilobytes and when millions of such requests are processed within your Microsoft Azure application.

ASP.NET View State is also a security risk when sending confidential data as part of view state to client. This data is vulnerable to attacks and can be tampered with by an attacker, which is a serious security threat.

Solution to ASP.NET View State Problems

You can resolve ASP.NET View State issues in Microsoft Azure applications by storing the actual ASP.NET View State on the server side in a distributed cache and never send it back to browser along with request payload.

NCache for Azure is an extremely fast and scalable distributed cache for Microsoft Azure. NCache for Azure allows you to store actual ASP.NET View State in Distributed Cache on server side and instead send a small token as view state to the client in a request payload. This dramatically reduces the request payload size. View State token is then used on the server side to find the right ASP.NET View State in NCache for Azure Distributed Cache on post backs. A smaller payload resolves issues related to performance and bandwidth utilization because you are not dealing with huge view state anymore on each request in your Microsoft Azure Application. Moreover, View State stored on the server side in NCache for Azure distributed cache is never exposed to clients so it addresses the above mentioned security concerns.

Here is an example of a token being used in place of ASP.NET View State with NCache for Azure ASP.NET View State provider:

[code lang=”csharp”]
<input type="hidden" name="__VIEWSTATE" id="__VIEWSTATE"
value="cf8c8d3927ad4c1a84dsadfgsdsfdsda7f891bb89185" />
[/code]

Using NCache for Azure ASP.NET View State Caching

Step 1: Create an app.browser file in App_browsers directory. Plug in page adapters in the app.browser file as follows:

   File: App_browsersapp.browser 

[code lang=”csharp”]
<browser refID="Default">
<controlAdapters>
<adapter controlType="System.Web.UI.Page"
adapterType="Alachisoft.NCache.Adapters.PageAdapter" />
</controlAdapters>
</browser>
[/code]

Step 2: Add the following assembly reference in compilation section of web.config file.

   File: web.config

[code lang=”csharp”]
<compilation defaultLanguage="c#" debug="true" targetFramework="4.0">
<assemblies>
<add assembly="Alachisoft.NCache.Adapters, Version=1.0.0.0,
Culture=neutral, PublicKeyToken=CFF5926ED6A53769"/>
</assemblies>
</compilation>
[/code]

Step 3: Register NCache for Azure config section in your web.config file.

   File: web.config

[code lang=”csharp”]
<configSections>
<sectionGroup name="ncContentOptimization">
<section name="settings"
type="Alachisoft.NCache.ContentOptimization.Configurations.ContentSettings"
allowLocation="true" allowDefinition="Everywhere"/>
</sectionGroup>
</configSections>
[/code]

Step 4: Specify settings for your config section in web.config file (that was registered above). These settings control NCache for Azure ASP.NET View State Caching features.

   File: web.config

[code lang=”csharp”]
<ncContentOptimization>
<settings viewstateThreshold="12" enableViewstateCaching="true"
enableTrace="false" groupedViewStateWithSessions="false"
<cacheSettings cacheName="myCache"
maxViewStatesPerSession="3">
<expirationtype="Absolute" duration="1"/>
</cacheSettings>
</settings>
</ncContentOptimization>
[/code]

Conclusion

NCache for Azure provides a no code change option for your Microsoft Azure applications to store ASP.NET View State on the server side in a Distributed Cache. NCache for Azure ASP.NET View State provider optimizes performance by reducing request payload and bandwidth consumption while addressing security issues related to client side View State.

Download NCache Open Source and run it Microsoft Azure.

Posted in ASP .NET performance, ASP.Net, ASP.NET View State, Distributed Cache, Microsoft Azure | Leave a comment

ASP.NET Output Caching in Microsoft Azure to Improve Performance

Microsoft ASP.NET Output Cache provides functionality to cache rendered content of ASP.NET pages or user controls for a specified duration. This allows your ASP.NET application to serve all subsequent requests from the cache instead of re-rendering and re-execution of a page.

You add the <% @OutputCache %> directive on the page to use ASP.NET Output Cache.

[code lang=”csharp”]
<%@Page … %>
<%@OutputCacheDuration="duration"VaryByParam="paramList"%>
[/code]

ASP.NET Output Cache is a very useful feature, especially for situations when a page is accessed more frequently than it changes and you serve it from cache. This improves application performance by avoiding page re-executions and also by reducing your expensive database trips especially when page involves a lot of heavy database operations. This also improves application scalability because the database generally becomes a scalability bottleneck when there are millions of such pages and requests involving database operations.

Problems with ASP.NET Output Cache in Microsoft Azure Environment

When you use ASP.NET Output Cache in Microsoft Azure then page output is stored as InProc within your Microsoft Azure Web Role by default. First issue with InProc ASP.NET Output Cache is that it limits you to the memory that is available on your Web Role instance and this may create an out of memory issue when you cache a large amount of page output data. Another issue is that your application runs on multiple load balanced Microsoft Azure Web Role instances. The next request might go to another Web Role instance, which creates a new copy of ASP.NET Output Cache data in this instance, as well. These redundant copies of page outputs in each Web Role instance consume a lot of extra memory.

Microsoft Azure Web Role instances also recycle quite frequently for maintenance and patching. When this happens, all page outputs are lost and you’ll have to re-execute all pages to re-populate your page Output Cache, which is a negative performance impact on your Azure application.

Solution to ASP.NET Output Cache Problems

One way you can resolve all these issues in Microsoft Azure is to use a distributed cache, which runs out-of-process and is a common store for all Microsoft Azure Web Role instances. ASP.NET 4.0 has introduced an extensibility point that helps developers to use any distributed cache of their choice as their ASP.NET Output Cache store.

Distributed cache is shared by all Microsoft Azure Web Roles for page outputs so there are no redundant copies made within individual web role instances. Microsoft Azure Web Roles become purely stateless so data is never lost when Web Roles are recycled. You can cache a huge amount of data in distributed cache by pooling memory resources of all cache servers together. Moreover, distributed cache reduces load on your database because you don’t have to go through page executions involving database calls in each Microsoft Azure Web Role instance separately.

NCache for Azure is an in-memory distributed cache for .NET applications deployed in Microsoft Azure cloud. NCache for Azure has implemented ASP.NET Output Cache provider which you can use to store ASP.NET page output in NCache for Azure and resolve all above mentioned issues. Additionally, NCache for Azure provides data reliability with replication as well as improves application scalability.

How to use NCache for Azure ASP.NET Output Cache Provider

You can use NCache for Azure ASP.NET Output Cache provider as follows without any code change to your Microsoft Azure ASP.NET application.

Step 1: Add Reference of NCache for Azure ASP.NET Output Cache provider assembly.

File: web.config

[code lang=”xml”]
<compilation debug="true "targetFramework="4.0">
<assemblies>
<add assembly= "Alachisoft.NCache.OutputCache,Version=x.x.x.x,Culture=neutral"/>
</assemblies>
</compilation>
[/code]

Step 2: Register NCache for Azure ASP.NET Output Cache Provider under <configuration> section and provide cache settings.

File: web.config

[code lang=”xml”]
<caching>
<outputCache defaultProvider ="NOutputCacheProvider" />
<providers>
<add name="NOutputCacheProvider" type="NCOutputCache.NOutputCacheProvider"
exceptionsEnabled="true" enableLogs="false" cacheName="mypartitionofReplicaCache"/>
</providers>
</outputCache>
</caching>
[/code]

Step 3: Add ASP.NET Output Cache directive on the page that you want to cache. 

[code lang=”csharp”]
<%@OutputCacheVaryByParam="ProductCategory"Duration="300"%>
[/code]

NCache for Azure ASP.NET Output Cache Features

NCache for Azure provides a rich set of features for caching and managing ASP.NET Output Cache. Below is a list of them:

  1. Specify duration for Page Output: NCache for Azure allows you to specify a duration for which you want to cache ASP.NET page output.
  2. Cache different versions of a page: NCache for Azure allows you to cache different versions of page depending on the various ASP.NET Output Cache directives such as VaryByParam,VaryByCustom, VaryByControl. Another version of page output is stored in distributed cache if a different param is received for a page request.
  3. Cache different portions of a page: You can also specify only portions of the page instead of caching entire page. This is for situations where you cache only static portion of the page and leave the dynamic part which is rendered at runtime.
  4. Implement Custom Hooks for ASP.NET Output Cache: NCache for Azure allows you to implement and register your custom hooks (interface) for page output. This is to attach some extended attributes to your page outputs such as NCache for Azure database dependencies, Tags, Groups, etc.

Conclusion

 As you have seen, distributed cache allows you to cache ASP.NET page outputs, which resolves your ASP.NET application issues with multiple load balanced Azure Web Roles.  NCache for Azure ASP.NET Output Cache provider helps improve ASP.NET application performance scalability and reliability.

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Event Driven .NET and Java Data Sharing using In-Memory Distributed Cache

These days, many companies are running both .NET and Java applications in their enterprise environment.  Often these applications need to share data with each other at runtime. The most common way they do that today is by storing the data in the database and having the other application poll and look for it. Some people also develop web services solely for the purpose of allowing Java applications to obtain data from .NET applications and vice versa.

The problem with the first approach is that data sharing cannot happen instantaneously because the other “consumer” application has to poll the database, which happens after some predetermined interval. It also has performance and scalabilities issues like any application accessing the database for data. As you know, a database cannot scale the same way that today’s applications can. This is because although you can linearly scale an application tier by adding more application servers, you cannot do the same at the database tier.

The second approach requires a lot of custom programming and essentially changing your application’s architecture just so you can share data with other applications, whether they’re .NET or Java. It would be much nicer if you could continue to develop each application for the purpose that it is being built and not worry about creating a custom framework for data sharing.

Runtime Data Sharing through a Distributed Cache

The second approach requires a lot of custom programming and essentially changing your application’s architecture just so you can share data with other applications, whether they’re .NET or Java. It would be much nicer if you could continue to develop each application for the purpose that it is being built and not worry about creating a custom framework for data sharing.

Ideally, you would want to have an event driven model where a .NET application can be notified whenever a Java application has some data for it and vice versa. But, as you know, .NET and Java are not inherently compatible for this kind of use.

This is where a distributed cache like NCache comes in really handy. NCache provides events that are platform independent and can be shared between .NET and Java. NCache also provides binary level data type compatibility between .NET and Java. This allows you to not only receive events, but also corresponding data in the form of objects and all of that without having to go through any XML based transformation for data sharing purposes.

NCache event notification framework enables you to register to be notified when different types of events occur within the cache cluster. This way, whenever there are any changes made to the data, either by .NET or Java applications, your application gets notified. Here is sample code using NCache item-based event for data sharing in Java:

[code lang=”java”]
import com.alachisoft.ncache.web.caching.*;

public void AddToCache()
{
CacheEventListener onItemRemoved = new CacheEventListner();
Cache cache = NCache.initializeCache("PORCache");
Employee emp = new Employee();
emp.setDept("Mechanical");

CacheItem cItem = new CacheItem(emp);
cItem.setItemRemoveCallback(onItemRemoved);
cache.insert("EMP-1000-ENG", cItem);
}

public class CacheEventListner implements CacheItemRemovedCallback
{

public void itemRemoved(String key, Object value,
CacheItemRemovedReason reason)
{
Employee emp = (Employee) key;
System.out.println("Employee Removed " + key + "Dept" + emp.getDept());
}

}

[/code]

NCache provides you different cached item level notifications like item-added, item-removed and item-updated. Applications can register interest in various cached item keys (that may or may not exist in the cache yet), and they’re notified separately whenever that item is added, updated or removed from the distributed cache by anybody for any reason. For example, even if an item is removed due to expiration or eviction, the item-remove event notification is fired.

Both .NET and Java applications can register interest for the same cached items and be notified about them. The notification includes the affected cached item as well, which is transformed into either .NET or Java, depending on the type of application.

Here is a sample code of using NCache item-based event for data sharing in .NET:

[code lang=”csharp”]
public void AddToCache()
{
Cache cache = NCache.InitializeCache("PORCache");
Employee emp = new Employee();
emp.Name = "David Rox";
emp.Dept = "Engineering";

cache.Insert("EMP-1000-ENG", emp, null,
Cache.NoAbsoluteExpiration,
Cache.NoSlidingExpiration,CacheItemPriority.Default);

//Register Callback to get notified of changes related to provided key
cache.RegisterKeyNotificationCallback("EMP-1000-ENG",
new CacheItemUpdatedCallback(OnItemUpdated),
newCacheItemRemovedCallback(OnItemRemoved));
}

void OnItemRemoved(string key, object value,CacheItemRemovedReason reason)
{
//Item is removed. Do something
Employee emp = (Employee) value;
Console.WriteLine("Employee Removed {0}, Name {1}", key, emp.Dept);
}

[/code]

In summary, with NCache you can not only share data between .NET and Java applications at runtime but can also use distributed events to notify applications of any change in data.

So, download a fully working 60-day trial of NCache Enterprise and try it out for yourself.

Download NCache Trial | NCache Details

Posted in data sharing, Data Sharing with Distributed Cache, Distributed Cache, Distributed caching, Distributed events, Event driven data sharing | Tagged , , | Leave a comment

ASP.NET Session State Store in Microsoft Azure

Microsoft Azure provides a platform for ASP.NET applications in the cloud. Very often, these applications are high transactional and mission critical in nature. Therefore, it is very important that these applications are able to scale and that there are no data loss if a web server goes down at any time.

ASP.NET Session State needs to be stored somewhere and its storage becomes a major performance and scalability bottleneck. In Microsoft Azure, you can store ASP.NET Session State in In-proc, SQL Azure (database), Azure Table Storage or in a distributed cache.

InProc Option

In-proc session storage option doesn’t work well in Microsoft Azure architecture. First of all, ASP.NET Session State is not shared between multiple instances of the Web Role in In-proc mode. Secondly, you end up using sticky sessions in Microsoft Azure, which may result in uneven load distribution. Additionally, sticky sessions involve extra configurations on your part as Microsoft Azure doesn’t use sticky sessions by default. Moreover, any Web Role instance going down due to failure or for maintenance will result in session data loss and this is obviously not acceptable.

Azure Table Option

Azure Table Storage is file based ASP.NET Session State provider, which is provided on an ‘as-is basis’ as a code sample, meaning it is not officially supported by Microsoft. It is intended for storing entities that are structured. Even though it is a cheaper option it is still not an ideal place to store ASP.NET Session State primarily because of performance as it is file based.

SQL Database Option

Microsoft Azure SQL Database can also be used as storage for ASP.NET Session State by using conventional ASP.NET SQLServer Mode. But, ASP.NET Session State object is stored in the database as a BLOB and relational databases were never really designed for BLOB storage. This causes performance issues and it is definitely a major scalability bottleneck for your Microsoft Azure ASP.NET application.

Distributed Cache Option

Distributed Cache provides an ideal storage for ASP.NET Session State in Microsoft Azure. For example you can use NCache for Azure which is a Microsoft Azure Distributed Cache for .NET applications. It is extremely fast and more scalable than all other Microsoft Azure options mentioned above and it also replicates sessions so there is no data loss if a cache server ever goes down. Moreover, you eliminate all issues related to session sharing as well as use equal load balancing that ensures full utilization of all of your Azure Web role instances.

How to Configure NCache in Azure ASP.NET Session State Provider?

NCache in Azure has implemented the ASP.NET Session State provider that can be used by Microsoft Azure ASP.NET applications. NCache in Azure uses Microsoft Azure VMs and formulates a dedicated caching tier. ASP.NET applications in Microsoft Azure can then be directed to use this Azure Distributed Cache for ASP.NET Session State storage.

The nice thing about NCache in Azure ASP.NET Session State provider is that it doesn’t require any application code changes. Simply modify your application web.config file as follows to use NCache in Azure as your Distributed Cache for ASP.NET Session State:

[code lang=”xml”]
<assemblies>
<add assembly="Alachisoft.NCache.SessionStoreProvider,
Version=x.x.x.x, Culture=neutral,
PublicKeyToken=CFF5926ED6A53769"/>
</assemblies>

<sessionState cookieless="false" regenerateExpiredSessionId="true" mode="Custom"
customProvider="NCacheSessionProvider" timeout="20">

<providers>
<add name="NCacheSessionProvider"
type="Alachisoft.NCache.Web.SessionState.NSessionStoreProvider"
sessionAppId="NCacheTest" cacheName= "TestCache"
writeExceptionsToEventLog="false" />
</providers>
</sessionState>
[/code]

Here are a few important benefits you achieve when you use NCache for Azure as your distributed cache for storing ASP.NET Session State.

  • Linear Scalability and Performance: NCache for Azure is based on dynamic clustering protocol, which allows you to add more servers to your cache at runtime. Your application can scale out linearly by adding more servers to your Azure Distributed Cache when your application load grows without changing application architecture.
  • Session Replication: NCache for Azure provides reliability support with help of replication. You can take application instances offline for maintenance, patching and for new releases without having to worry about any session data loss.
  • High Availability: NCache for Azure provides fault tolerant support of high availability as it is based on hundred percent peer to peer architecture. It is guaranteed that you will not lose any data or have any application downtime in case of any node failure from distributed cache.

Conclusion

Azure Distributed Cache such as NCache in Azure is the best option for storing ASP.NET Session State in Microsoft Azure primarily because of performance, scalability, reliability and high availability features. Microsoft Azure Distributed Cache offered by NCache for Azure is very easy to use and doesn’t require any application code changes.

Download NCache for Azure Trial | NCache for Azure Details

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