Colocation hosting

Posted Posted by Patrice Guay in Web hosting     Comments 2 comments
Mar
17

Colocation is a hosting option for those who want the benefits of a web hosting provider (robust network infrastructure, electrical power redundancy, cooling equipment, etc.) and still own their server hardware. The upfront cost of a colocation server is higher than the one for a dedicated server. However, the monthly fee is lower in colocation since you do not have to pay the server hardware location fee.

Cost

The purchase of your server equipment represents the main upfront cost for a colocation solution and caution should be taken to optimize this investment. While a standard tower server may prove to be less expensive for the same hardware specifications, the rackmount form-factor is often seen as the standard and space-efficient format for servers in a datacenter. Some web hosting companies are offering single tower server colocation space which could be interesting if your web solution is running on only one server. However, if you need to run your web solution on more than one server to achieve high availability or better performance, I advise to choose a multi-server colocation space (a quarter rack or more) and use rackmount servers. In such a configuration, tower servers would waste your valuable colocation space.

For a multi-server colocation solution, there will be additional hardware in your colocation space:

  • Public network switch, required (1U)
  • Power Distribution Unit, required (1U for an horizontal device)
  • Private network switch, optional but recommended (1U)
  • Keyboard/Video/Mouse console, optional (1U)

Hence, a quarter rack solution with 12U of raw space will provide 9U of usable space if it is equipped with a public switch, an horizontal PDU unit and a private network switch. Depending on your web hosting provider, some of this equipment may be included in the colocation contract. The remaining equipment will be part of your upfront cost. Also, an additional setup fee for your colocation space may be required from your hosting provider.

The monthly fees for your hosting solution are linked to the footprint of your colocation space, your bandwidth requirements and the electricity consumed by your equipment. If the web hosting company is charging you for each electrical circuit of your colocation solution, you should try to evaluate as precisely as possible your power requirements. There are some web hosting companies offering metered power to their colocation customers where you only pay for the power you use, not the standard full rate circuit charge. This feature could be interesting in a situation where you only need the electrical power of one 15Amps circuit but require two circuits to provide electrical redundancy.

Resource allocation

A few years ago, the clock speed was a good metric to evaluate the performance of a CPU. Now, with the advent of multi-core CPUs, a high clock speed is not the only parameter to evaluate. For example, a quad-core CPU with a lower clock speed will outperform a single-core CPU on a multi-threaded application like a web or a database service. Improved multi-thread support will accelerate the processing of simultaneous tasks on your server.

Memory (RAM) of a server is also an important element since it provides caching space for regularly accessed data. While a Linux operating system will require a minimum of 256MB of RAM to run without a graphical interface, a Windows server will require a minimum of 1GB of RAM to function properly.

The size of hard drives grew rapidly during the last years and a server with a storage capacity of a few terabytes is no longer expensive, especially if it is built with SATA drives. However, using SATA drives instead of SAS or SSD drives will result in lower disk Input/Output performance for your server. A server equipped with SAS 15k RPM drives will provide twice as much I/O performance compared to SATA 7.2k RPM drives. Higher disk I/O performance is desirable for databases while the required storage capacity is usually low. The use of low capacity SAS or SSD drives will serve you better than SATA drives for such configurations.

A single-server colocation contract will typically include a monthly bandwidth commitment. Excess usage is charged at a flat rate per GB. If you expect a high level of traffic for your web server (10Mb/s or more), you should make sure this level of traffic will be available for your server by talking with your web hosting company. Since your colocation web server will most likely be connected with other colocation servers on a shared public switch, your actual bandwidth with the Internet can fluctuate depending on your neighbour usage. For example, if you share a 100Mb/s public switch with 20 other colocation servers and your switch is connected to the web hosting company routers on a 100Mb/s uplink, the actual bandwidth of your server will fluctuate between 5Mb/s and 100Mb/s. The use of a dedicated public switch solves this possible issue. Such a product is usually included in multi-server colocation spaces.

Uptime

There are several factors that will influence the uptime of your web solution:

  • application stability
  • server hardware stability
  • network uptime
  • electrical power uptime
  • temperature stability
  • operator skills

The stability of your web application is your sole responsibility on a colocation web hosting solution. If you need support for your web hosting solution, a colocation web hosting solution is not appropriate.

The hardware stability of your server is also a relevant factor for the uptime of your web solution. If a server hardware fails, the server will have to be replaced in order to restore your web presence. Disk failure is a critical event and should be planned by opting for a redundant RAID configuration at purchase time and taking regular backups of your sensitive information.

If the network connection between your server and the Internet is broken, your web solution will be unavailable for your visitors. Unless you made a modification to the network parameters of your server, a network connectivity problem is usually the symptom of a problem on your web hosting provider end. A web hosting provider with a responsive 24/7 support will allow you to restore connectivity in a timely fashion.

The uptime of the electrical power delivered to your server and network equipment will also influence the global uptime of your web solution. A serious web hosting company will use uninterruptible power supply (UPS) and generators to maintain electrical power to your server and their network infrastructure during blackouts.

Keeping your server and network equipment at a reasonable temperature is also a crucial element for your colocation solution. A failure to maintain an acceptable temperature (30°C or below) will force your servers to shut down. This type of outage is critical since the overheat of your servers may break some key components like their CPU, their disks or thier motherboard.

Error during manual maintenance by the datacenter operators can cause downtime to your colocated servers. A datacenter with unlabelled network or electrical equipment is most likely exposed to such human errors. Moreover, your manual intervention in your colocation space could be the source of downtime. Labelling your own equipment (power cables, network switches, servers, hard disks, etc) could reduce the occurrence of these manipulation errors.

Monitoring probes are a great tool to continuously check for the uptime of your web solution. It could advise you automatically in case of a downtime. You should seek this service to protect your web presence and reduce the length of downtime.

Scalability

If your web solution can not run properly on a single colocation server, you will need to scale up by adding new colocation servers to your setup. The first step is usually to host the web and the database services on two different servers. You can scale up further by duplicating your web and database servers to provide redundancy and an higher throughput. If your web solution includes more than four servers, opting for a multi-server colocation plan instead of multiple single-server plans will most likely reduce the overall costs of your solution. Moreover, having your servers regrouped on a single location inside the datacenter will ease the maintenance of your hardware.

Interconnecting your colocation servers on a private switch will allow your servers to communicate locally on a private network. The network traffic on such a connection is free of charge.

Support

There are basically four layers of management on a web hosting solution:

  • datacenter layer: electricity, cooling, physical security, fire protection, building maintenance
  • networking layer: Internet connectivity, activity monitoring, IP addresses provisioning
  • server equipment layer: server installation, cabling, hardware maintenance
  • application layer: OS installation, OS updates, application installation and configuration

Most web hosting providers will provide support for the datacenter and networking layers on a colocation solution. You will need to support the server equipment and the application layers of your web solution by yourself. Choosing a web hosting providers close to your location is crucial as critical server equipment maintenance will require your presence in front of your colocation servers.

Some colocation vendors offer a remote “hands and eyes” service to provide on-site assistance. Technicians capable of following basic instructions to complete simple physical tasks are then dispatched on demand within your colocation space. Complex tasks will require your presence however.

Conclusion

Colocation web hosting is a compromise between an homemade web solution and a dedicated server. Like a dedicated server solution, the datacenter and networking aspects of your web solution are managed by the web hosting company. However, you own the server equipment and manage the application layer of your solution. Therefore, the colocation facility must be within a reasonable distance from you, as any issues with devices, operating systems and applications must be handled by yourself.

2 Comments to “Colocation hosting”

  • Which co-location providers are good enough ?

  • As stated in the conclusion of this article, the colocation facility must be within a reasonable distance from you. Here in Montreal (Canada), Peer1, Canix and iWeb are providing good quality co-location hosting.

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