WEB HOSTING

Dedicated hosting service


Dedicated hosting service


A dedicated hosting service, dedicated server, or managed hosting service is a type of Internet hosting where the client leases an entire server not shared with anyone. This is more flexible than shared hosting, as organizations have full control over the server(s), including choice of operating system, hardware, etc. Server administration can usually be provided by the hosting company as an add-on service. In some cases a dedicated server can offer less overhead and a larger return on investment. Dedicated servers are most often housed in data centers, similar to colocation facilities, providing redundant power sources and HVAC systems. In contrast to colocation, the server hardware is owned by the provider and in some cases they will provide support for your operating system or applications.
Operating system support
Availability, price and employee familiarity often determines which operating systems are offered on dedicated servers. Variations of Linux (open-source operating systems), are often included at no charge to the customer. However, Microsoft requires additional license fees on all their products, thus increasing the monthly cost of a dedicated server running a Windows operating system. Commercial operating systems include Microsoft Windows Server, provided through a special program called Microsoft SPLA. Red Hat Enterprise is a commercial version of Linux offered to hosting providers on a monthly fee basis. The monthly fee provides OS updates through the Red Hat Network using an application called up2date. Other operating systems are available from the open source community at no charge. These include CentOS, Fedora Core, Debian, and many other Linux distributions or BSD systems FreeBSD, NetBSD, OpenBSD.

Support for any of the operating systems above typically depends on the level of management offered with a particular dedicated server plan. Operating system support may include updates to the core system in order to acquire the latest security fixes, patches, and system-wide vulnerability resolutions. Updates to core operating systems include kernel upgrades, service packs, application updates, and security patches that keep server secure and safe. Operating system updates and support relieves the burden of server management from the dedicated server owner.
Bandwidth & Connectivity
Bandwidth refers to the data transfer rate or the amount of data that can be carried from one point to another in a given time period (usually a second) and is often represented in bits (of data) per second (bps). For example, visitors to your server, web site, or applications utilize bandwidth as the traffic moves from your server to the Internet and vice versa. Connectivity refers to the “access providers” that supply bandwidth, or data transfer rate, through various connection points across a network or footprint to one or multiple data centers where dedicated servers are housed.

Bandwidth measurements are defined (per telecom standards) as the following:
First – 95th (measured using average bits and speed of transfer)
Second – Unmetered (measured in speed or bits)
Third – Total Transfer (measured in bytes transferred)

95th Method: Line Speed, billed on the 95th percentile, average or peak usage, refers to the speed in which data flows from the server or device. The measurement can be compared to mph (Miles Per Hour), or how fast something travels. Line Speed is measured using bits per second, kilobits per second, megabits per second, and gigabits per second.

Unmetered Method: The second bandwidth measurement is Unmetered service where providers cap or control the “top line” speed for a server. Top line speed in Unmetered bandwidth is the total Mbit/s allocated to the server and configured on the switch level. For example, if you purchase 10 Mbit/s Unmetered bandwidth, the top line speed would be 10 Mbit/s. 10 Mbit/s would result in the provider controlling the speed transfers take place while providing the ability for the dedicated server owner to not be charged with bandwidth overages. Unmetered bandwidth services usually incur an additional charge.

Total Transfer Method: Some providers will calculate the Total Transfer, the measurement of actual data leaving and coming from the server, measured in bytes. Measurement between providers varies and includes one of the following equations:

Method 1: IN TRAFFIC + OUT TRAFFIC = TOTAL TRANSFER
Method 2: IN TRAFFIC = TOTAL TRANSFER
Method 3: OUT TRAFFIC = TOTAL TRANSFER

One of the reasons people choose to outsource dedicated servers is the availability of high powered networks from multiple providers. As dedicated server providers utilize massive amounts of bandwidth, they are able to secure lower volume based pricing to include a multi-provider blend of bandwidth. To achieve the same type of network without a multi-provider blend of bandwidth, a large investment in core routers, long term contracts, and expensive monthly bills would need to be in place. The expenses needed to develop a network without a multi-provider blend of bandwidth does not make sense economically for hosting providers.
Many dedicated server providers include a SLA (Service Level Agreement) based on network uptime. Some dedicated server hosting providers offer a 100% uptime guarantee on their network. By securing multiple vendors for connectivity and using redundant hardware, providers are able to guarantee higher uptimes; usually between 99-100% uptime if they are a higher quality provider. One aspect of higher quality providers is they are mostly likely multi-homed across multiple quality uplink providers, which in turn, provides significant redundancy in the event one goes down in addition to potentially improved routes to destinations.

Bandwidth consumption over the last several years has shifted from a per megabit usage model to a per gigabyte usage model. Bandwidth was traditionally measured in line speed access that included the ability to purchase needed megabits at a given monthly cost. As the shared hosting model developed, the trend towards gigabyte or total bytes transferred, replaced the megabit line speed model so dedicated server providers started offering per gigabyte.
Prominent players in the dedicated server market offer large amounts of bandwidth ranging from 500 gigabytes to 3000 gigabytes using the “overselling” model. It is not uncommon for major players to provide dedicated servers with 1Terabyte (TB) of bandwidth or higher. Usage models based on the byte level measurement usually include a given amount of bandwidth with each server and a price per gigabyte after a certain threshold has been reached. Expect to pay additional fees for bandwidth overage usage. For example, if a dedicated server has been given 3000 gigabytes of bandwidth per month and the customer uses 5000 gigabytes of bandwidth within the billing period, the additional 2000 gigabytes of bandwidth will be invoiced as bandwidth overage. Each provider has a different model for billing. As of yet, no industry standards have been set.
Management
To date, no industry standards have been set to clearly define the management role of dedicated server providers. What this means is that each provider will use industry standard terms, but each provider will define them differently. For some dedicated server providers, fully managed is defined as having a web based control panel while other providers define it as having dedicated system engineers readily available to handle all server and network related functions of the dedicated server provider.
Server management can include some or all of the following:
Operating System Updates
Application Updates
Server Monitoring
SNMP Hardware Monitoring
Application Monitoring
Technical Support
Firewall Services
Anti-Virus Updates
Security Audits
Backups and Restoration
Disaster Recovery
DNS Hosting
Load Balancing
Database Administration
Performance Tuning
DDOS Protection and Mitigation
Software Installation, Configuration
Intrusion Detection
User Management
Programming Consultation
Dedicated hosting server providers define their level of management based on the services they provide. In comparison, fully managed could equal self managed from provider to provider.
Administrative maintenance of the operating system, often including upgrades, security patches, and sometimes even daemon updates are included. Differing levels of management may include adding users, domains, daemon configuration, or even custom programming.
Dedicated server hosting providers may provide the following types of server managed support:
Fully Managed - Includes monitoring, software updates, reboots, security patches and operating system upgrades. Customers are completely hands-off.
Managed - Includes medium level of management, monitoring, updates, and a limited amount of support. Customers may perform specific tasks.
Self Managed - Includes regular monitoring and some maintenance. Customers provide most operations and tasks on dedicated server.
Unmanaged - Little to no involvement from service provider. Customers provide all maintenance, upgrades, patches, and security.
Note: The provider will continue to maintain security on the network regardless of support level.
Security
Providers often bill for dedicated servers on a fixed monthly price to include specific software packages. Over the years, software vendors realized the significant market opportunity to bundle their software with dedicated servers. They have since started introducing pricing models that allow dedicated hosting providers the ability to purchase and resell software based on reduced monthly fees.

Microsoft offers software licenses through a program called the Service Provider License Agreement. The SPLA model provides use of Microsoft products through a monthly user or processor based fee. SPLA software includes the Windows Operating System, Microsoft SQL Server, Microsoft Exchange Server, Microsoft SharePoint and shoutcast hosting, and many other server based products.

Dedicated Server Providers usually offer the ability to select the software you want installed on a dedicated server. Depending on the overall usage of the server, this will include your choice of operating system, database, and specific applications. Servers can be customized and tailored specific to the customer’s needs and requirements.

Other software applications available are specialized web hosting specific programs called control panels. Control panel software is an all inclusive set of software applications, server applications, and automation tools that can be installed on a dedicated server. Control panels include integration into web servers, database applications, programming languages, application deployment, server administration tasks, and include the ability to automate tasks via a web based front end.

Most dedicated servers are packaged with a control panel. Control panels are often confused with management tools, but these control panels are actually web based automation tools created to help automate the process of web site creation and server management. Control panels should not be confused with a full server management solution by a dedicated hosting provider.
Limitations
Many providers do not allow IRC (eggdrops, clients or daemons). This is due to rogue IRC users triggering DDoS attacks against the provider, which may overwhelm their networks, lowering service quality for all customers.
Adult content is disallowed by many providers as it may either be of questionable legality or consume large amounts of bandwidth.
Spam is usually prohibited by the provider's Acceptable Use Policy.
External Links


Website hosting services at the Open Directory Project
Dedicated hosting guide
Dedicated Server Guides

Posted by smarty at 12:46 PM 0 comments

Virtual private server









VIRTUAL PRIVATE SERVER !!!




A virtual private server (VPS, also referred to as Virtual Dedicated Server or VDS) is a method of partitioning a physical server computer into multiple servers that each has the appearance and capabilities of running on its own dedicated machine. Each virtual server can run its own full-fledged operating system, and each server can be independently rebooted.
The practice of partitioning a single server so that it appears as multiple servers has long been common practice in mainframe computers, but has seen a resurgence lately with the development of virtualization software and technologies for other architectures.


Overview

The physical server boots normally. It then runs a program that boots each virtual server within a virtualization environment (similar to an emulator). The virtual servers have no direct access to hardware and are usually booted from a disk image
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There are 2 kinds of virtualizations: software based and hardware based. In a software based virtualization environment, the virtual machines share the same kernel and actually require the main node's resources. This kind of virtualization normally has many benefits in a web hosting environment because of quota incrementing and decrementing in real time with no need to restart the node. The main examples are Virtuozzo (a product of swsoft.com), HyperVM (a product of lxlabs.com), Vserver, and OpenVZ which is the core kernel of both virtuozzo and hypervm.

In a hardware based virtualization, the virtualization mechanism partitions the real hardware resources and no burst and/or realtime quota modification is possible. The limits are hard and only modified after a restart. This kind of environment is more secure and is useful in enterprise/commercial usages. Examples include Microsoft Virtual Server, VMware ESX Server, and Xen


Uses

Virtual private servers bridge the gap between shared web hosting services and dedicated hosting services, giving independence from other customers of the VPS service in software terms but at less cost than a physical dedicated server. As a VPS runs its own copy of its operating system, customers have superuser-level access to the machine, and can install almost any software that runs on the OS. Certain software does not run well in a virtualized environment, including firewalls, anti-virus clients, and indeed virtualizers themselves; some VPS providers place further restrictions, but they are generally lax compared to those in shared hosting environments. Due to the number of virtualization clients typically run on a single machine, a VPS generally has limited processor time, RAM, and disk space.

Due to their isolated nature, VPSes have become common sandboxes for possibly-insecure public services or update testing. For example, a single physical server might have two virtual private servers running: one hosting the production-level (live) website, and a second which houses a copy of it. When updates to crucial parts of software need to be made, they can be tested in the second VPS, allowing for detailed testing to be conducted without requiring several physical servers.

Virtual private servers are also sometimes employed as honeypots, allowing a machine to deliberately run software with known security flaws without endangering the rest of the server. Multiple honeypots can be quickly set up via VPSes in this fashion


Virtualization software

User-mode Linux
vmware
Microsoft Virtual Server
qemu
VDSmanager
Virtualbox
xensource
parallels
OpenVZ
HyperVM
Virtuozzo
FreeVPS
FreeBSD jail
Solaris Containers (Zones)

Posted by smarty at 12:36 PM 0 comments






WEB HOSTING !!!!









A web hosting service is a type of Internet hosting service that allows individuals and organizations to provide their own websites accessible via the World Wide Web. Web hosts are companies that provide space on a server they own for use by their clients as well as providing Internet connectivity, typically in a data center. Webhosts can also provide data center space and connectivity to the Internet for servers they do not own to be located in their data center, called colocation.


Service scope

The scopes of hosting services vary widely. The most basic is webpage and small-scale file hosting, where files can be uploaded via File Transfer Protocol (FTP) or a Web interface. The files are usually delivered to the Web "as is" or with little processing. Many Internet service providers (ISPs) offer this service for free to their subscribers. People can also obtain Web page hosting from other, alternative service providers. Personal web site hosting is typically free, advertisement-sponsored, or cheap. Business web site hosting often has a higher expense.
Single page hosting is generally sufficient only for personal web pages. A complex site calls for a more comprehensive package that provides database support and application development platforms (e.g. PHP, Java, and ASP.NET). These facilities allow the customers to write or install scripts for applications like forums and content management. For e-commerce, SSL is also required.


The host may also provide an interface control panel (e.g. cPanel, Plesk or others) for managing the Web server and installing scripts as well as other services like e-mail. Recently, Web.com holds many patents it claims cover broad methods for website building and web control panels. Hostopia, a large wholesale host, recently purchased a license to use that technology from web.com for 10% of retail revenues. Web.com recently sued Go Daddy as well for similar patent infringement

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Some hosts specialize in certain software or services (e.g. e-commerce). They are commonly used by larger companies to outsource network infrastructure to a hosting company. To find a web hosting company, there are searchable directories that can be used. One must be extremely careful when searching for a new company due to the fact that many of the people promoting service providers are actually affiliates and the reviews are biased.


Hosting reliability and uptime

Hosting uptime refers to the percentage of time the host is accessible via the internet. Many providers state that they aim for a 99.9% uptime, but there may be server restarts and planned (or unplanned) maintenance in any hosting environment.
A common claim from the popular hosting providers is '99% or 99.9% server uptime' but this often refers only to a server being powered on and doesn't account for network downtime. Real downtime can potentially be larger than the percentage guaranteed by the provider. Many providers tie uptime, and accessibility, into their own Service Level Agreement, or SLA. SLAs may or may not include refunds, or reduced costs if performance goals are not met.


Types of hosting

Internet hosting services can run Web servers; see Internet hosting services.
Hosting services limited to the Web:

Free web hosting service: is free, (sometimes) advertisement-supported web hosting, and is often limited when compared to paid hosting.
Shared web hosting service: one's Web site is placed on the same server as many other sites, ranging from a few to hundreds or thousands. Typically, all domains may share a common pool of server resources, such as RAM and the CPU. A shared website may be hosted with a reseller.

Reseller web hosting: allows clients to become web hosts themselves. Resellers could function, for individual domains, under any combination of these listed types of hosting, depending on who they are affiliated with as a provider. Resellers' accounts may vary tremendously in size: they may have their own virtual dedicated server to a colocated server.

Virtual Dedicated Server: slicing up a server into virtual servers. each user feels like they're on their own dedicated server, but they're actually sharing a server with many other users. The users may have root access to their own virtual space. This is also known as a virtual private server or VPS.

Dedicated hosting service: the user gets his or her own Web server and gains full control over it (root access for Linux/administrator access for Windows); however, the user typically does not own the server. Another type of Dedicated hosting is Self-Managed or Unmanaged. This is usually the least expensive for Dedicated plans. The user has full administrative access to the box, which means the client is responsible for the security and maintenance of his own dedicated box.

Managed hosting service: the user gets his or her own Web server but is not allowed full control over it (root access for Linux/administrator access for Windows); however, they are allowed to manage their data via FTP or other remote management tools. The user is disallowed full control so that the provider can guarantee quality of service by not allowing the user to modify the server or potentially create configuration problems. The user typically does not own the server. The server is leased to the client.

Colocation web hosting service: similar to the dedicated web hosting service, but the user owns the colo server; the hosting company provides physical space that the server takes up and takes care of the server. This is the most powerful and expensive type of the web hosting service. In most cases, the colocation provider may provide little to no support directly for their client's machine, providing only the electrical, Internet access, and storage facilities for the server. In most cases for colo, the client would have his own administrator visit the data center on site to do any hardware upgrades or changes.

Clustered hosting: having multiple servers hosting the same content for better resource utilization.

Grid hosting : relatively a new web hosting buzz, this form of distributed hosting is when a server cluster acts like a grid and is composed of multiple nodes. Being highly fault tolerant, this system is breaking new grounds when it comes to the network stability factor

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Some specific types of hosting provided by web host service providers:

File hosting service: hosts not web pages but files
Image hosting service
Video hosting service
Blog hosting service
One-click hosting
Shopping cart software



Obtaining hosting

Web hosting is often provided as part of a general Internet access plan; there are many free and paid providers offering these services.

A customer needs to evaluate the requirements of the application to choose what kind of hosting to use. Such considerations include database server software, scripting software, and operating system. Most hosting providers provide Linux-based web hosting which offers a wide range of different software. A typical configuration for a Linux server is the LAMP platform: Linux, Apache, MySQL, and PHP/Perl/Python. The webhosting client may want to have other services, such as email for their business domain, databases or multi-media services for streaming media. A customer may also choose Windows for its hosting platform. The customer still can choose from PHP, Perl, and Python but may also use ASP .Net or Classic ASP.
Web hosting packages often include a Web Content Management System, so the end-user doesn't have to worry about the more technical aspects.

One may also search the Internet to find active webhosting message boards that may provide feedback on what type of webhosting company may suit his/her needs.