Microsoft Silverlight is a programmable web browser plugin. It enables many features such as vector graphics, animation, and audio-video playback all these applications are rich internet applications. Version 2.0 of Microsoft Silverlight was released in October 2008. It got some additional interactive features and support for .NET languages and development tools. It is compatible with many web browsers used on Microsoft Windows and Mac OS X operating systems. Symbian phones and Windows Mobile 6 will also be supported. New third party free software named Moonlight is under development. Once released it will bring compatible functionality to GNU/Linux.

Similar to Windows Presentation Foundation Silverlight provides retained mode graphics system. It also integrates graphics, multimedia, interactivity and animations into a single runtime environment. Silverlight is designed to work in conjunction with XAML and is scriptable with JavaScript. XAML is used for marking up the vector graphics and animations. If you create textual content using Silverlight, it’s searched and indexed by search engines. The textual content is not compiled, but represented as text (XAML). Windows Sidebar gadgets for Windows Vista can also be created using Silverlight.

Playback of media files like WMA, MP3 and WMV is also supported by Silverlight across all the supported browsers. For the playback Silverlight doesn’t need Windows Media Player ActiveX control or Windows Media browser plugins. Windows Media Video 9 is an implementation of the SMPTE VC-1 standard; Silverlight supports VC-1 only in ASF container format. Adding to that the software license agreement says VC-1 is only licensed for the “personal and non-commercial use of a consumer”. Silverlight doesn’t provide support for H.264 video. With Silverlight it possible to dynamically load XML content that can be manipulated through a DOM interface. This technique is consistent with conventional Ajax techniques. A Downloader object which can be used to download content, like scripts, media assets or other data as per the requirements of the application is also installed in the Silverlight.

Silverlight applications can be written in any of the .NET programming languages. Therefore any development tools that can be used .NET languages can work with Silverlight. For this process development tools have to target Silverlight CoreCLR instead of .NET framework CLR. Microsoft Expression Blend version 2.0 and 2.5 are assigned the job of designing the UI of Silverlight 1.0 and 2, by Microsoft. To develop and debug Silverlight applications Visual Studios 2008 can be used. For creating Silverlight projects and allowing compiler to target CoreCLR, Visual Studio 2008 requires the Silverlight Tools for Visual Studio.

A Silverlight project consists of the Silverlight.js files and CreateSIlverlight.js files which initialize the Silverlight plugin for use in, a XAML file for the UI, HTML pages and code-behind files for the application code. Just like ASP.NET applications Silverlight applications are debugged. Visual Studio’s CLR Remote Cross Platform Debugging feature can be used Silverlight applications running on a platform as well. Eclipse was added as a development tool with Silverlight 2.0.

Social Bookmarking

How to Set up a Microsoft SQL Web Server cluster

Types of clusters

A cluster is basically referred to as grouping of similar things to reduce the load or work of a single one. When it comes to servers there are 2 types of clusters :

1) Load Balancing Web Server ;

Load balancing Web Server is setup so that the traffic load is distributed among a number of servers instead of one single server. It involves a number of servers which are setup in such a way that the traffic is equally distributed among all of them. Due to this kind of a setup, the network load is not concentrated on one single server and this helps in improving the reliability with the tremendous improvement in performance. This kind of setup is also available for 2 or more nodes in the cluster.

2) Failover cluster Server :

Failover cluster also involves a number of servers but this is not the same as Load Balancing servers. Failover, as the term suggests, is setup to provide high availability even after there is an hardware or software failure. Once there is a software or an hardware failure, an action is taken by the cluster immediately so that the resources of the server are moved to another server. Cluster is informed once the hardware of software failure has taken place as the cluster keeps on monitoring the resources.

Real time failover for hardware and software failures including the current status of the applications can be acheived by fault-tolerant failover cluster. But this requires a better software application and more hardware and this is due to the fact that the condition of the current applications must be known. The applications which are currently in use are lost while the failover process is going on by the hardware and the software components and these should be recovered.

Microsoft’s Cluster Service (also known as MSCS) is exactly opposite to the true fault-tolerant cluster and is built in as a high-availability cluster. This is better as the cluster will not require specialized fault-tolerant solution and can work with more applications with less hardware also. This will definitely reduce the price. The cluster will not be in a good position after the failover but will be able to recover from a hardware or software failure. Two servers (nodes) are supported by the MSCS high-availability solution.

Basic hardware and software components

A common set of hardware is involved which are actually two servers nodes in a cluster. Both the servers in the cluster are connected to the network and both of them have there own operating system. The harddisks are external but they are connected to the servers through a network. A drive controller connects the shared disks to the servers. A Storage Area Network (SAN) is commonly used for this purpose.

Only one of the nodes in the cluster is active at a time. They are not active together and hence this solution is also called as an active/passive solution. The resources of the cluster is used up by the active server (node) and the active server writes all the data on the Shared disks. If one node fails the other one comes into play. To make sure that all the nodes are working properly, a signal known as a heartbeat is sent accross the private network to which all the servers are connected. If the active server fails, the passive server gets a signal about it through the heartbeats and once it receives the signal, it starts working as an active server and starts using all the resources of the cluster.

How to Install SQL Server in a cluster ?

Operational cluster is required to install SQL server in the cluster. Follow the steps given below to install Operational cluster.

1) First, install a Windows Server edition which supports MSCS on each server.

2) Now, make sure that each server in the cluster is connected to a Public network which is required to receive requests.

3) Make a different network and all the servers shouldn’t be connected to this network as this network should only be established between two servers within the cluster. This network will only be used for the heartbeats to send signals.

4) You will have to create a user account for the service account so that the cluster operates under this account in the domain. Make sure that you add this account to each Administrator’s group of each server.

5) Now you will have to connect the Shared harddisks to the server and you will have to power off the servers for this purpose. Once you connect the Shared harddisks to the servers make sure that the resources are being used by the server. Turn on node number one of the cluster.

6) Install Microsoft Cluster service and then configure it through control panel. Follow the steps given below to do this.

a. Go to Control Panel.

b. Then, Add/Remove Programs

c. Finally, Windows Components

7) You will have to give a name to your cluster and also assign an IP address with the Shared disk resources.

Now turn on the second node in the cluster and move to the First one (Original one) once the second one is online. Once you get back to the original one, to add another node use the Cluster Administrator.

Note : You will be able to install the second node quite easily in comparison to the first one as it will be based on the configuration of the second one.

Once you have installed the cluster sucessfully and everything works fine, follow the steps given below to install SQL server into the cluster :

1. To begin the installation process, you will have to insert the SQL Server Enterprise edition CD. If the installation does not start auto-matically, launch the setup through setup.exe.

2. Select Virtual Server on the computer name screen and enter a name by which you would like the Cluster be referred.

Note : This name is a Virtual name and is just like the hostname of a server.

3. Now make a service account to run the SQL web server and make sure that you provide Administration rights on each node on the cluster.

4. You will have to assign an IP address, Shared Resources and a service account to the SQL server while the installation.

Once you have done all the above steps correctly, a copy of SQL Server server will be installed on each node by the setup program within the cluster and the setting of the cluster will be installed automatically. Now you will be able to control the SQL server services by the cluster administrator.

Social Bookmarking

Sub-domain management is very much similar to main domain name configuration. The main difference is that it is attached to the main domain name. Request for subdomain is routed to DNS server which has DNS information for the main domain. Sub-domain DNS records resolved to a IP address, the rquest is sent to the web server that is assigned with the IP address. the request can now be moved to the website. By many DNS server entries, subdomain configuration can be taken care of and application setup for management of load or applications.

DNS server should have pointer to the sub domain as CNAME or hostname or MX entry for emails. If the IP address of the main domain name and sub-domain name are the same, we then use CNAME or alias. A records are used if the IP points to the different dedicated server in case of load balancing server setup.

CNAME is used when the IP address of the sub-domain and the main domain are the same. It means the parent domain and child-domain points to the same IP address such as :

www IN CNAME domain.com.
subdomain1 IN CNAME domain.com.
subdomain2 IN CNAME domain.com.

A record is setup when the main domain is different from the sub-domain. This is in case of a load balancing or server cluster setup such as :

subdomain1 IN A 123.2.33.45.
subdomain2 IN A 123.2.33.46.

MX records are mail exchanger sub-domains in case of email setup that will be pointing to the dedicated web server IP address and used for different email account such as :

subdomain1 IN MX 10 subdomain1.domain.com.
subdomain2 IN MX 10 subdomain2.domain.com.

If the sub-domain is configured on a different DNS name server, nameserver records is created for the sub-domain. Different nameservers can reduce security issues.

DNS Server sends the request for the sub-domain to the IP address, it starts functioning. It then needs to be configured to manage the request based on the IP address / Host headers. It is utilized by web servers to host different domains / sub-domain on one IP address.

In a Windows dedicated server, we have to use IIS manager to add sub-domains that will be assigned to IP address. Port is then set to 80. Host header can be added by clicking on advanced tab nect to IP address configuration for website application. Sub-domain that points to sub-directory of website which is then home directory for the sub-domain.

In a Linux dedicated server, we use Apache web server which is configured by virtual host entry in httpf.conf :

Listen 80
NameVirtualHost *

ServerName www.domain.com
DocumentRoot /home/httpd/htdocs/

ServerName subdomain.domain.com
DocumentRoot /home/httpd/htdocs/subdomain/

Social Bookmarking

Linux Plesk Dedicated Servers and Windows Web Servers both support Plesk as control panel. Plesk is very easy to manage on a dedicated server. Features such as Domain Management, Email, MySQL and MS SQL Database Management and much more. Website uploads with a few clicks, domain bakcups, FTP, Crontabs, SpamAssassin Setup, Plesk Reseler Dedicated Features and many more all are important features of a Plesk Dedicated Server.

BODHost Recommends Plesk as Control Panel while opting for a Windows Dedicated Server Plesk can easily integrate with databases and if we opt for Plesk add-on’s such as Plesk Power Pack, it helps us to integrate SQL Database with Plesk Control Panel and Dr. Web Anti-virus sacns for viruses on the VPS.

Social Bookmarking

Security and protection is very important when it comes to dedicated servers. Setting up Windows Dedicated Server Firewall basically refers to devices which allow or deny traffic or any incoming or outgoing connections based upon set of rules. It normally operates within a single network or over various networks in large operations. It prevents any network threats. It’s architecture is to block any vulnerable threats to the main server. On a linux server, we can also configure IPtables or csf firewall through cPanel.

It basically filters packets or units of data transfers basically TCP and UDP traffic. Cisco are known for their firewall appliances which ofcourse compete with other appliances such as Juniper. Some of the linux firewall include Cisco ASA, Coyote Linux etc. Windows Operating Systems offer in-built Firewall, famously known as Windows Firewall. However, we can also configure hardware firewall such as Cisco etc.

Security is a very important concept today and it definitely needs implementation on every dedicated server.

Social Bookmarking