Can
Your Business Afford Downtime?
Can Your Business Afford Downtime?
Hardware failures, software failures or user error can all cause
system downtime. Downtime causes customer dissatisfaction, additional
customer support, lost revenue and impacts your reputation. When
your web site goes down, you're losing potential customers and risking
existing ones.
The problem is, the majority of web hosting companies have no redundancy
in place, with one server handling all requests. A hard disk failure,
power supply failure or software issue will bring all websites on
that server off line. It may take hours to repair the problem, leaving
customers stranded. Carefully read the fine print when choosing
a web hosting company. Most provide uptime guarantees that only
cover network uptime, not service availability. That way, They guarantee
this because as long as the network is functioning, regardless of
whether or notif your web site is up, the uptime guarantee is being
met.
High Availability refers to an architecture designed for very high
uptime. A High Availability solution greatly reduces the risk of
downtime by integrating spare devices that will take the place of
any resource that becomes unavailable. A High Availability infrastructure
has redundancy starting at the network level all the way to the
server level.
A High Availability network will connect to multiple backbone carriers
and have fully redundant routers /and switches. A provider, router
or switch failure should not affect your website. Power systems
should be fully redundant including auto transfer to a backup generator
in the event thatof grid power failures. Power distribution units
should be redundant and never overloaded.
Temperature and humidity should be controlled by multiple air conditioning
units, with enough additional capacity to maintain the environment
in the event of an AC unit failure.
Servers designed for High Availability include dual power supplies
and a RAID (redundant array of inexpensive disks (RAID).) If a power
supply fails, a backup will instantly take its place. The failed
power supply can be replaced without bringing the server down. RAID
refers to using multiple hard disks which appear as one. If one
of the hard drives in a RAID fails, no data is lost and only a small
performance penalty occurs while the array is rebuilt using a spare
hard disk.
Redundant power supplies and RAID are key components in a High
Availability infrastructure, although it can be taken a step further.
Clustering is a term you may have heard before. Fail over is a type
of clustering that dramatically increases service availability.
In a fail over cluster, two servers are linked together. One is
actively handling requests, while the other stands by. If the primary
server should fail, the secondary server will detect this and automatically
take over. The switch should take place within seconds, with little
noticeable effect to your sites’ visitors. Fail over clustering
can protect against total server failure, including file system
corruption or critical hardware failure (such as the processor or
motherboard.) It can take hours to re-build or provision a new server
after a failure, clustering eliminates this possibility.
Monitoring the state of a High Availability infrastructure is equally
important as the redundant hardware itself. The network, server
and application layer need to be closely monitored on a continual,
24x7 basis. Technicians trained in High Availability need to be
available around the clock to instantly respond to any issues that
arise. Monitoring should be performed from an off site and off network
location, to ensure a true perspective on service availability.
A hosting environment designed for maximum uptime includes redundant
network, power, cooling, data storage, server hardware and proactive
monitoring. If you have a mission critical web site that you depend
on, make sure your next host has an infrastructure designed for
High Availability.
About the Author Grant Supp is the owner
of Inthrive (www.inthrive.com),
a web hosting company founded in 2003 with the mission of providing
High Availability clustered web hosting at affordable prices. Experience
the rock solid stability of Inthrive's’ High Availability
web hosting.
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