When the basin is small, or it's time to choose VPS server
Recommendations for the analysis of the characteristics and proper the choice of VDS hosting. Is intended to read the users who need to make a decision on the expediency of transferring web projects with a large load on the web server (forum, media portal, online store) hosting virtual dedicated server.
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1. When the Internet project has outgrown shared hosting
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1.1. What is VDS
Virtual dedicated server — VDS (virtual or VPS private server) is created with the help of special programs and technology mini-server, limited in resources, but much more than moschny web hosting fully private and controlled by its owner.
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1.2. Signs of increased load on the hosting
In the process of development of the Internet project comes one of three possible situations:
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- When the site starts to open more than 4 seconds, every day becomes unavailable, and from a technical hosting support come the angry letters about the excess load on the CPU and memory on the web server. Typically this happens owing to the increase in database size MySQL, used in most modern CMS # because of the increasing number of visitors to the web site. The development of any forum, blog or social network be new members, you receive more and more messages, comments. People visit the website more often. From this the load on the server CPU due to database queries grows so large that it already violates the rules of the hosting. For example: HostGator, their the rules, item 7a, prohibits the MySQL query for more than 15 seconds, or use more than 25% of system resources longer than 90 seconds. the
- When the further development of the Internet project requires the use of scripts or modules to the web server, which require individual adjustment of the operating system of the server and therefore can't work on shared hosting. For example, a mail server (Sendmail , Postfix or Exim), FTP — server or the Nginx web server. the
- When it is necessary to solve some security issues, for example, prevent access to files by unauthorized persons or to abandon FTP and replace it with #SFTP.
At this stage, the owner of the site think about porting your projects to a VDS hosting. VDS hosting often seen as a compromise in a situation when the power and functionality of shared hosting for $3 — $7 a month is already enough, and a dedicated server at a price from $150 to $300 is still too expensive. VDS (Virtual Dedicated Server) virtual private server service is a software emulation of a real physical server. VPS (Virtual Private Server) virtual private server, refers to the meaning the same as VDS but with the difference that, in practice, applies only to virtual servers based on OpenVZ/Virtuozzo, which provides virtualization at the kernel level of the OS and is less reliable than other technologies (XEN, KVM, etc.).
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2. Comparison of shared hosting and VDS
One of the most common misconceptions about the use of VDS is that any website will always run faster on a virtual server than regular web hosting. In fact, it even has VDS and dedicated server, but virtual and hence the database server MySQL, mail server, all services will be performed on it within its limited resources (there are exceptions as some managed VDS).
Unlike web hosting where all clients access a shared database server, often hosted on a separate physical server and running on a powerful hardware platform. Also, on the VDS, depending on the virtualization technology, there may be problems with hard disk performance during high-intensity file operations (a common problem on VPS with OpenVZ/Virtuozzo).
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3. Types of VDS in terms of support
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3.1. Unmanaged
In the case of unmanaged VPS company-web hosting is only responsible for the smooth operation of the hosting and availability of the network for your virtual server. You get a VDS with the operating system and need to install and configure all the necessary programs (control panel, web server, mySQL server, mail server). This option is cheaper but requires good knowledge of the administration server from the user database.
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3.2. Managed
In this case, you, as the owner of the VDS can count on tech support to set up or use virtual server. For you would be pre-installed and configured the server administration panel and a set of common software (Apache,MySQL,PHP, FTP server, mail server). The cost of renting a VDS will be much more, but is convenient for those users who want to do their website, and not to dig into the settings of the virtual server.
For example, system administrators Acenet responsible for:
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- as a regular OS updates, installation of patches and security updates the
- round-the-clock health monitoring virtual server the
- monitoring and response to system messages about full disk, the actual script limits is dedicated to running server resource the
- perform a backup the
- installation and configuration of various software, servers, and modules to them
| Unmanaged | Managed | What is configured in the managed variant | |
| Acenet | $19.95 | $79.90 |
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Table 1. The difference in the value of managed and unmanaged VDS
Also the concept of managed VDS common feature included to place resource-intensive program such as the MySQL database server on a separate physical server, reducing the load on the virtual server of the client.
InMotion hosting understands managet VDS:
| What makes hosting technical support | What does the client itself |
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Table 2. The composition of free services administration, managed VPS InMotion Hosing
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4. Types of virtualization when used for hosting web sites
When you create a virtual machine concepts are used:
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- Host OS — the operating system installed on the physical server (host computer) the
- Guest OS — the operating system installed on the virtual server
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4.1. Virtualization at the kernel level of the OS
In this case, the operating system creates separate containers in a virtual machine. For users of these containers look like a copy of the server with reduced resources. Program and system processes in different containers can't influence each other. Access to resources and their separation between the VMS provides the basic operating system. Using this technology it is impossible in a virtual machine to run a guest operating system different from the host OS. Examples of such systems used in the industry of hosting are Virtuozzo and FreeBSD Jail.
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4.2. Virtualization hypervisor-based
The technology uses a hypervisor program or electronic circuit, which is installed on the host computer and enables the creation, launch and operation of several virtual machines. All virtual machines are completely isolated and independent from each other. The hypervisor leverages partnoy virtualization and creates an environment that simulates the hardware of a physical server, wherein the guest operating system may not know what runs in the virtual environment. The guest operating system may be any of those operating systems that support hypervisor and the different virtual machines. Examples of hypervisor are Xen and KVM.
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5.1. OpenVZ (and its commercial version Virtuozzo)
This is one of the first and the most widely used virtualization technology, for example, among participants Best 10 VPS Hosting Providers only one company — Acenet offers VDS based on Xen technology use OpenVZ/Virtuozzo. OpenVZ open source development, distributed free of charge. On OpenVZ based company Parallels was designed by Virtuozzo. This technology is based on OS Linux. Virtuozzo is easy to install and configure. But keep in mind that all virtual servers use a single core, so individually you can't include the needed modules for the individual VPS memory and disk space shared, is shared among all virtual servers within the allocated limit.
This means that neighboring VPS, creating a load on the file system a large number of disk operations, create a problem and cause slow down your and all the other virtual servers. In connection with the use of one common core operating system on virtual servers you can not put another OS.
Also, the use of shared resources provides an opportunity for the owners of hosting overselling. The overselling is a situation where the server administrator expects that the client in most cases will not use all of the resources that should be at the rate of. Therefore, the resources of the physical server are distributed to a larger number of virtual machines than can be operated simultaneously at full capacity. For example, on a physical server installed 4Gb RAM and it is distributed over 512 MB 10-20 virtual machines instead of eight.
Because, in reality, most customers do not use all resources that should be at the rate, the problems will only arise during peak load or when the application starts, which, for example, really takes all selected tariff memory. The virtual machine may be only the same OS as the server.
Figure 1. Control panel OpenVZ
In fact, the only two advantages of VPS based on Virtuozzo is:
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- lower cost to customers compared to virtual servers based on Xen or KVM. the
- possibility to change server settings (e.g., size of memory, number of allocated CPU time, disk size, virtual machine) without rebooting .
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5.2. Xen
This is a much more stable technology. Due to the fact that for each virtual server runs its own kernel, the user fully controls the system and not depend on other users and their actions on the own VDS-Ah. Due to the complete isolation from each other, each virtual server can run a different operating system, and the available resources (memory, disk space) exactly match the value in accordance with the tariff. Also, very importantly, any disasters on the individual VDS will not affect the speed and stability of neighbors on the server.
For example, if on a separate VDS any process taking all the memory or create too many file operations, slow down or stop working, only this virtual server, and the other VDS will continue to function normally. When using this technology on a virtual server, you can install various operating systems such as Linux, NetBSD, FreeBSD, OpenBSD, Windows XP, or 2003 Server.
Figure 2. Organizatsiia VDS using XEN technology
The main features of Xen: support the regime in addition to paravirtualization hardware virtualization, the ability to migrate a running virtual machine between physical machines( for example, cloud server). In the simplest case, the system physically can run two nodes on virtual machines distributed among them, and their CDs are duplicated and stored on both nodes.
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5.3. KVM
A virtualization technology which works at the kernel level of the operating system (why it's called Kernel-based Virtual Machine) and supports hardware virtualization. For the user of VDS, this means virtually no performance loss because of virtualization, high reliability and stability.
Figure 3. Organization of virtual machines in KVM technology
Advantages of KVM technology:
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- independent and isolated dedicated disk space and dedicated memory for each virtual machine. the
- network protocols support allows to install and use VPN the
- support for physical access to the console can monitor the virtual server boot time. the
- support any operating systems on virtual servers.
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5.4. Hyper-V
Virtualization technology from Microsoft, powered by Windows Server 2008. Used hardware-assisted virtualization. The performance loss is negligible. Allowed guest OS: Windows NT, 2000, 2003, 2008, XP, Vista, Linux Red Hat or Linux SUSE. Other guest operating systems on Linux are not supported.
Figure 4. The architecture of Hyper-V.
In this technology there is no USB support for virtual machines, the virtual machines do not hear the sound. This technology is recommended if you plan to use a VDS with Windows.
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5.5. FreeBSD Jail
Is a virtualization technology which allows on the basis of a FreeBSD system installed on the physical server to create multiple operating in isolation FreeBSD virtual machines. Use common core operating system, but virtual machines are configured completely individually. None of the processes running inside a Jailed process cannot affect any external processes. Other operating systems as a guest cannot be used.
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5.6. VMWare
Is used for virtualization product VMware ESX/ESXi Server. ESX allows you to create a fully isolated virtual machine, physical server resources are divided into logical sections. Currently, this virtualization platform is used for the organization of cloud hosting. For the organization of VDS is used very rarely.
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5.7. The differences between the most popular platform for VDS
In reality, the virtual server for the purposes of web hosting, as a rule, are created on the basis of the three most popular technologies: KVM, OpenVZ/Virtuozzo, Xen.
Figure 5. The results of the vote on the popularity of virtualization technologies, from the website webhostingtalk.com
A comparison of the advantages and disadvantages of these technologies are shown in Table 3.
| KVM | OpenVZ/Virtuozzo | Xen | |
| Private file system of any type | + | - | + |
| the Allocated region in RAM with full access and debugging capabilities | + | - | + |
| Complete isolation from neighbors | + | - | + |
| a VNC connection in the early stages of loading | + | - | limited |
| PPTP VPN | + | limited | + |
| OpenVPN | + | limited | + |
| IPSec VPN | + | - | limited |
| Firewalls (Firewall) | + | limited | + |
| Kernel mode NFS server | + | - | - |
| Independent core | + | - | limited |
| Independent kernel modules | + | - | limited |
| Full control on sockets and processes | + | - | - |
| Full guest OS support (Windows, Linux, BSD, OpenSolaris, etc.) | + | - | limited | Emulation of PCI / PCIe cards with full access to it | + | - | limited | the
| Formal integration with the Linux kernel | + | - | + |
Table 3. Comparison of virtualization technologies KVM, OpenVZ/Virtuozzo and Xen
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6. The selection criteria for virtual server
Usually, if you need virtual server, this means that will accommodate either a large resource intensive project, for example, store (www.dsw.com), news portal (militarytimes.com) or social network (www.caringbridge.org) or a specific service that cannot run on shared web hosting (e.g. mail server). Any of these options implies a greater burden on the hosting side scripts and a large attendance. When choosing a VDS it is necessary to consider several factors.
Considering the three groups, the quality of the hosting service, the cost and level of service received, the following criteria:
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- virtualization Technology although the most popular technology is OpenVZ/Virtuozzo and historical reasons, as a pioneer, and thanks to the low cost, it is better to choose VDS hosting based on more stable technologies XEN, KVM, or Hyper-V. Of the ten leaders, offering virtual servers (http://webhostinggeeks.com/vpshosting.html) VDS technology XEN only offers Acenet. the
- memory — in addition to memory allocated to your VPS in the Virtuozzo still have Burstable Memory is additional memory that your scripts can be short-term use through overuse their own resources (assuming that no other users took Burstable Memory at this point). the
- disk space disk space which will accommodate all your files, html pages, scripts, databases, statistics, e-mail. the
- monthly traffic do not forget that your traffic is consumed not only when visiting your sites, but at the injection sites in the hosting, installing CMS when downloading and installing scripts and performing reserves of kopirovanija to your local hard disk. the
- the size of the used CPU time — an important indicator, which determines what fraction of processor power from the server to use your VPS. Unfortunately, this indicator is conditional and in practice it is impossible to compare the various providers of VPS hosting because of the various providers on servers that use different processors and the user does not know what it was. For example, of the ten leaders of the rating http://webhostinggeeks.com/vpshosting.html none of the hosting provider did not specify the characteristics of the physical servers that host VDS and only Acenet I have a share of CPU, though in a completely incomprehensible units (vCPU). the
- Geographical location of the datacenter — the closer to the main audience of your website the more likely visitors will be pleased with the loading speed of web pages. For example, if you test the speed of file download from data center InMotion Hosting on the East coast, the download time for users in San Francisco (about 1.9 seconds) and Washington (0,36 seconds) will vary 5 times#. Ideally, it is good to have a choice of several options, for example, InMotion Hosting there are data centers on the West and East coast of the United States (http://goo.gl/UvJVv). the
- operating system Type VDS. It is better to choose CentOS, Debian, Ubuntu that are different with a stable job on virtual servers and a large number of reference information for those who are poorly versed in system administration. FreeBSD is a good, reliable operating system, but requires a good knowledge in administration. Windows makes sense to choose only for specific program requirements (for example, when using MSSQL database server or ASP scripts) that you will run into VDS. the
- the cost of the additional administration — you need to understand what costs are waiting for you in situations where you do not deal with the server administration yourself. If you rent a Managed VDS, the cost of support will be included in the VDS payment. the
- support. The schedule and timetable of technical support. Methods of communication: telephone, tickets, LiveChat, mail email. the
- hosting Reviews from real users (support in reality, overselling, real uptime servers). the
- trial period — the period of time during which the rules of the hosting you can request a refund. This is important because only practice will show you the actual CPU power of the server and the actual resources of the virtual server to those described in the tariffs.
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7. Conclusion
Thus, the placement of one or more web sites on a virtual dedicated server is an important decision that should be taken, having considered all the arguments for and against.
Advantages of VDS:
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- ability to run scripts which require more memory and CPU time the
- full user control over access to his files the
- ability to customize the web server to fit your needs
The use of VDS is:
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- large costs of hosting compared to shared hosting the
- need to be able to administer Linux or Windows servers, or the
- charges for services system administrator
most user's responsibility for the performance of their websites
Figure 7. The structure of the server with the VPS.
Also, always remember that there are two factors that will allow you to compare different virtual server providers exactly all the characteristics written in rates:
- as often uses the technology of OpenVZ/Virtuozzo, web hosting can and often is engaged in overselling, i.e. for example offers in the tariff plans of RAM for each VPS and more than the amount of memory is physically there on the server. This leads to the fact that at peak load on one virtual server will not have enough resources for another. How the administration is hosting abusing the possibility of overselling, you will be able to learn only in practice, or reviews from other users.
One of the main indicators of the capacity of the virtual server — the proportion of CPU time does not have a common unit of measurement, can be measured in Mhz, can in percent of CPU time virtual CPUs or even not be specified, but in any case, these units are not comparable for different hosting providers. the
Why pick a virtual server not only technical characteristics but also for reviews of other users.
| Rank | Web Hosting Provider | Core Specs | Features | Hosting Review |
| 1 | Inmotion Ultra Fast Servers |
Space: 80 Gb Bandwidth: 1000 Gb Price: $74.95 |
Free & Easy Setup 5 Dedicated IPs Full cPanel/Fantastico |
Inmotion Review |
| 2 | UltraHosting Cheap VPS Solutions |
Space: 40 Gb Bandwidth: 1500 Gb Price: $54.00 |
Free & Easy Setup 1 Dedicated IP |
UltraHosting Review |
| 3 | NS Secure VPS Hosting |
Space: 50 Gb Bandwidth: 2000 Gb Price: $80.00 |
Free & Easy Setup 1 Dedicated IP Virtuozzo/ Plesk 9 |
NS Review |
| 4 | Acenet High Performance Servers |
Space: 40 Gb Bandwidth: 1500 Gb Price: $109.95 |
Free & Easy Setup Full cPanel/Fantastico |
Acenet Review |
| 5 | hostican has Affordable VPS Hosting |
Space: 90 Gb Bandwidth: Unlimited Price: $84.95 |
cPanel/WHM/Plesk, 2 Dedicated IPs |
hostican has Review |
| LiquidWeb Reliable VPS Hosting |
Space: 40 Gb Bandwidth: 350 Gb Price: $100.00 |
Free & Easy Setup 4 Dedicated IPs, Full cPanel/Fantastico |
LiquidWeb Review |
|
| 7 | Dotster Cheap VPS Hosting |
Space: 30 Gb Bandwidth: 1000 Gb Price: $48.95 |
Free & Easy Setup 2 Dedicated IPs, Virtuozzo/Plesk 9 |
Dotster Review |
| 8 | Lunarpages Linux & Windows VPS |
Space: 20 Gb Bandwidth: 1000 Gb Price: $49.95 |
Free & Easy Setup 1 Dedicated IP Virtuozzo Power Panel |
Lunarpages Review |
| 9 | 1&1 Internet Cheap VPS Hosting |
Space: 50 Gb Bandwidth: 2000 Gb Price: $59.00 |
Free SSL Certificate 1 Dedicated IP CentOS 5 + Plesk 9 |
1&1 Review |
| 10 | XL Host Cheap VPS Hosting |
Space: 10 Gb Bandwidth: 250 Gb Price: $59.00 |
Free & Easy Setup 4 Dedicated IPs, Tons of Extras |
XL Host Review |
Table 5. The leaders of the rating VDS hosting with a website webhostingw.com
And immediately after the purchase, try to actively test your VDS for the maximum load in the initial period, while it is possible to request a refund.
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