It is defined as a server-based product that returns files to clients when requested. These files are typically returned in the form of Web pages to a client Internet browser. There are different types of web servers such as the virtual web server, personal web server and the apache web server.
A web server is a computer including software package providing a specific kind of service to client software running on other computers. It is a program that uses the client/ server model and the World Wide Web's Hypertext Transfer Protocol (HTTP), serving the files which form Web pages to Web users.
Web Servers Explained: All machines on the Internet fall under two basic categories of clients and servers. Machines that provide services to other machines are identified as servers. The machines that are used to connect to those services are called clients. When a user connects to Yahoo! at www.yahoo.com to read a page, Yahoo! is actually providing a machine for use on the Internet, to service user request. In other words, Yahoo! is providing a server.
The user machine becomes the client. It is possible and common for a machine to be both a server and a client at the same time. A server machine may provide one or more services on the Internet. The server could have software running on it that allows it to act as a Web server, an e-mail server and an FTP server.
Common Web Servers
Personal Web Server (PWS): Personal web server can be defined as Microsoft's version of a web server program for individual PC users. It is used to share Web pages and other files from the hard drive. PWS is described as a scaled-down version of Microsoft's robust Web server called the Internet Information Server i.e. the IIS. PWS can be used with a full-time Internet connection to serve Web pages for a Web site with limited traffic.
Active Server: The active server is a technology that enables the construction of dynamic and interactive web pages. It uses server-side scripting to produce web pages that are not affected by the type of browser the web site visitor is using.
Causes of Server Data Loss: RAIDs are amongst the most complex media devices to recover data from. The data configurations are complex such as striped, volume and spanned. Human error accounts for more than 35% of data loss in RAID systems.
Accidental deletion of files
Accidental deletion of partitions
Accidental reformatting of drives
Accidental replacement of media components
Actuator failure
Natural disasters of fire and flood leading to data loss
Data theft, employee sabotage and hacking
Directory corruption
RAID incorrect configuration
Electro static discharge or ESD leading to a power spike causing burnout and failure
Virus attacks and worm damage
Human error of physical movement, mishandling and poor maintenance
Controller malfunction
Locked databases preventing access
Forgotten or lost password
Server Data Recovery: Losing valuable data and experiencing extended downtime costs organisations thousands or even millions of pounds. Server data recovery entails recovery of lost data from file servers, application servers, web servers, direct-attached RAID, network-attached storage and large SAN storage area network systems. Server data recovery follows a multiple approach to be used on any type of storage system, configuration and situation.
Any server make, model or brand
All types of RAID configurations
Any operating system i.e. Windows, Linux, UNIX
All causes of data loss i.e. data loss resulting from natural disasters, power loss or surge, logical or mechanical failures and viruses
The Process:
The drives in the RAID are numbered
Complete forensically sound images of each of the drives are taken. This includes the redundant drives.
Data reconfiguration into a ‘virtual RAID' on a multi terabyte server is done
File listing of recovered files is done
The RAID system is taken to the clean room and opened
The recovered data is copied onto a new drive in accordance with client demand
Technology: Technicians are clean room trained. Precision technology and a regulated environment offer full data protection confidentiality. Usually, all professional data recovery companies engaging in server data recovery have ISO 9001:2000 Quality Assurance.
The technology used can resolve combinations of logical and physical problems. These include disk crash, controller failures, SQL and Exchange corruption. The damages also cover tape overwrite or EOD errors, accidental file deletion, operating re-installations, drive read errors, hardware upgrade failures and restore failures.
Raid Server Data Recovery
Advantages:
?The main advantage of a RAID drive is that it increases the performance and reliability of the system. The RAID drive is a convincing example that could be used in a server.
?Mirroring is the complete duplication of data. In other words mirroring is the 100 redundancy. Only copying to the replacement is necessary.
?Mirroring & Striping - The performance of a server increases when Disk stripping is done - RAID Level 0+1 requires a minimum of 4 drives to implement. This is actually done by the interleaving of bytes or a group of bytes. The interleaving of this sort is done across multiple drives. Reading and writing of the data are done in a simultaneous process. High I/O rates are achieved by striping RAID 1 segments.
?The RAID regularly checks for any possibility of a system crash by increasing the parity check.
?The concept of parity comes after the concept and application of mirroring. Data from the crashed system is matched with the data stored in the other disk. This is called Parity. Parity is used to calculate the data in the two drives and store the results in the third drive. In case there are more than two drives parity check is done on all of them and the results are stored on a completely different drive. The preferable device may be the RAID 3 (Striping With Dedicated Parity) or RAID 5 (Striping With Distributed Parity). Very high rate of transfer when data is being accessed in large chunks sequentially.
Disadvantages:
?A major disadvantage regarding the RAID drive is that drivers for a Network Operating System (NOS) need to be written. The most important usage of the RAID system is that it is primarily designed and widely used in a server. So when the server comes into the picture, there obviously has to be a network. Hence the device drivers should be included so as to design the system. The design is a quite complex process as far as the RAID is concerned.
?Administrators find it very difficult to configure a RAID system. The ability to dynamically enlarge the RAID server is also a complex process; especially for those administrators who are the IS managers and also LAN administrators.
?Another main disadvantage is that the system should support RAID drives. Most of the RAID drives include the different types like the RAID 0, RAID 1, and RAID 2 etc. Hence if the server system is using a different type of RAID drive and that is not supported by the system, then the problem of availability may arise.
?Initially one has to determine the type of RAID drives that is compatible. Different system supports different types of RAID drives. DGR (Storage Dimensions Dynamic Growth) technology allows the administrator of any network system to reconfigure the Storage Dimensions RAID System.
Though there are disadvantages, the RAID system offers a lot of expansion and constancy and the advantages are one up on disadvantages. Hence RAID is still the most widely used server.
Both James Wallis & Nahar Dijla are contributors for EditorialToday. The above articles have been edited for relevancy and timeliness. All write-ups, reviews, tips and guides published by EditorialToday.com and its partners or affiliates are for informational purposes only. They should not be used for any legal or any other type of advice. We do not endorse any author, contributor, writer or article posted by our team.
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