Uptime explainedWhat is Uptime Explained

Uptime is the measure of the uninterrupted time that a hosting system experiences. Ideally uptime would be at 100% (i.e. zero downtime) but in the real world this is extremely difficult to achieve.

In layman’s terms, Uptime is the number of hours that a server is working and available and is the opposite of downtime.

Why Is Uptime Important?

Uptime is important because it means that your hosting is available. If your site is not available then obviously this has a negative impact on your business. Customers and potential customers can not see your website so you may lose business. You can not send or receive emails. Maybe Google sees that your website is unreliable and this negatively affects your ranking.

How Is Uptime Calculated

Uptime is calculated based on the number of hours that the system (server) is available during a given period of time and is expressed as a percentage.

For example, annual uptime is calculated as follows:

Number of hours or uptime divided by Number of hours per year multiplied by 100

Let’s look at an example. We know that there are 365 days per year so in terms of hours there are a total of 365 x 24 = 8760 hours.

So if there was 4 hours of downtime per year then that would mean that there are 8756 of uptime (i.e. 8760 hours minus 4 hours downtime). So the calculation would be:

(8756 / 8760) x 100 = 99.95%

So in this case the uptime is 99.95%

What Uptime Does Pickaweb Offer?

Pickaweb offers a 99.9% uptime but we usually exceed this.

How Can High Uptime Be Guaranteed?

In order to offer a high level of uptime many factors come into play. High levels of uptime can only be achieved with an end to end approach that includes the following:

  • Datacentre
  • Racks
  • Servers

Let’s look at each in turn.

Datacentre Uptime

A Datacentre is a multi-million pound investment with one aim in mind. To ensure high uptime and data availability. This is achieved by using multiple, redundant systems to ensure that one failure will not result in downtime as there are backup systems in place.

These cover electrical backups through failover systems and standby generators with contracts in place for additional fuel in the event of any major issues. Also the datacentre has separate points of entry for key electrical supplies so that if there is a power interruption to one supply they service will not be interrupted.

Also in terms of environmental control the equipment housed in a datacentre has specific environmental requirements in terms of temperature and humidity. Various cooling and humidity systems are in place to ensure an optimum operating environment.

In terms of security the Datacentre has very strict access controls starting at the front gate to ensure no unauthorised entry. These include biometric controls and man traps.

From a safety perspective this is built into the Datacentre design so fire detection and suppression systems play a vital role.

Uptime also requires high levels of data connectivity. There are multiple data suppliers who access the datacentre at separate physical points to eliminate the possibility of downtime due to data connectivity issues.


Servers are stored in racks which are like special cabinets designed to hold servers. The racks use dual power feeds in from the Datacentre’s main power supply so that a failure of one power supply will not affect the rack.

Server Uptime

The most common source of downtime though is at the server level. Servers consist of a number of components that could lead to failure such as power supplies and hard drives.

In order to mitigate against downtime and to ensure high levels of uptime the following measures can be taken:

Dual Power Supplies – All of our hosting servers use dual power supplies to ensure that the server continues functioning normally in the event of a power supply failure

Use of RAIDRAID stands for Redundant Array of Inexpensive Disks and is a way of storing data across multiple hard drives via a RAID Controller so that in the event of a hardware failure on one drive there is no loss of data or interruption of the service. With Pickaweb’s Shared and Reseller Hosting Plans we use RAID 10 with hot swap hard drives.

Hot Swap Hard DrivesHot Swap Hard Drives are a type of drive that can be removed whilst the server is operational and can be replaced in the RAID Array to ensure a high level of uptime.

Cloud Virtual Server – With a Cloud VPS data is stored in several physical servers thereby dramatically improving Uptime. This can also be referred to as High Availability Hosting.

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