hooman nili

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Website Hosting Part 2
hooman nili
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Background
So far, so
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Hosting a new website
1. Choosing and registering a domain The first
step in creating a new domain is choosing a name
and a TLD (top level domain) and performing a
search for availability. If available, new domain
names can then be registered through a registrar
or an agent who will try to register domain on
your behalf.
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Hosting a new website
Some notes about domains - Uniqueness - TLD vs
second-level domains - Availability Real-time
registration - Lifetime / registration period -
Ownership - whois
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Hosting a new website
2. Setting up / configuring DNS servers Once a
domain name is registered it needs to be set
up/configured. The process involves updating the
DNS records for the domain making sure the domain
points to the correct DNS servers. A domain
needs, at least, two DNS servers (not necessarily
on two different nodes).
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Hosting a new website
Example Domain myee1160.org DNS servers
(records) dns1.howell001.net ns2-a.libraray005.or
g Questions?
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Hosting a new website
3. Setting up hosting services After (or at same
time) DNS records are configured, the provider
will need to set up your web space, mail servers,
ftp, etc. Domains may need several days to be
fully propagated.
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Hosting a new website
4. Uploading files Going live After your web
space (hosting account) is set up, the host will
send your access details which typically includes
your username(s) and password(s) for various
services as well as some information about the
servers (urls, ips, etc). You can then upload
your files to your web space using FTP or similar
methods. Note FTP before propagation
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Three Attributes of Smooth Hosting
Web hosting is not just about a set of features
and quite often web designers overlook other
important aspects of web hosting, which should
not be taken for granted. There are at least
three important elements we need to consider in
order to run our website smoothly
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Three Attributes of Smooth Hosting
1. Security All the measure taken by the host
(and us) to minimise the risk of unauthorised
access to certain services.
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Three Attributes of Smooth Hosting
2. Reliability Provision of services as expected
e.g. accuracy, as well as availability
(uptime). For most webby situations, we
interchangeably use reliability and availability
i.e they refer to the same thing.
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Uptime - The 9s Table (double-chk!)

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Three Attributes of Smooth Hosting
3. Scalability Ability to continue serving our
website as it grows.
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The Big Picture
Providers Network
Internet DNS Infrastructure Local,
regional, and root servers
Server
Server
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High Availability
Services availability can usually be associated
with 1. Single point of failure
(SPOF)/Redundancy 2. Providers management/admin
policies 3. Developers skills and users
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High Availability
Uptime Uptime is interpreted by different people
in different ways. As far as the web designer is
concerned it should refer to the amount of time a
web site is available to users, but its often
more complicated than this Uptime
Guarantee 99.99 Uptime Guarantee?
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Uptime - The 9s Table

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High Availability Side Note
Marketing Opportunity Uptime Guarantee What
does it mean? 99.99 Uptime Guarantee
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Example Terms and Conditions
 100 Uptime Guarantee We guarantee that
your website will be up all through the year!
However, if your website uptime should be lower
than 89.9, we will give you a full refund of
your hosting charges for that particular effected
month. Please see your Acceptable Use Policy
(AUP) for additional details.
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High Availability
Clustering In order to decrease the chance of
downtime, several nodes can be set up to provide
the same service. Clustering refers to a model
for grouping a number of machines in order to -
Boost performance Load balancing - Provide
redundancy - Failover
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High Availability
Load Balancing Load balancing refers to the model
in which data (e.g. web pages) is distributed
across more than one server. Since all servers
keep identical data, its important to ensure
proper synchronisation data across the cluster.
Clustering is therefore a relatively expensive
option.
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High Availability
Load Balancing Load-balanced servers can also
benefit from the High Availability model. Servers
in a Highly available (HA) cluster can also
benefit from multiple redundant components e.g.
multiple power supplies. This is usually known as
N 1 redundancy.
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High Availability
Load Balancing Load-balanced servers can also
benefit from the High Availability model. Servers
in a Highly available (HA) cluster can also
benefit from multiple redundant components e.g.
multiple power supplies. This is usually known as
N 1 redundancy.
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Example 1 Simplified HTTP redundancy
Server 1
Server 2
Server 3
Stand-by mode
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Example 2 High Availability Design
Public Network 1
Public Network 2
NIC 1
NIC 1
NIC 2
NIC 2
Monitoring link 1 (Heartbeat 1)
Monitoring link 1 (Heartbeat 2)
Storage 2
Storage 1
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Question Time

• Is 100 uptime possible?
• Is clustering always the best option?
• What is Global DNS Load Balancing?

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Useful Links

• http//www.dns.net/dnsrd/rfc/rfc2182.html
• http//www.nominet.org.uk/