Topic - Server Technology by jizhen1947


									                                               Revision Server Technology 1

Topic - Server Technology
1. Review the role of servers in modern IT support
2. RAS is a common term used in server deployment – Explain the term
3. x86 servers are very popular
Justify this popularity
Explain what is meant by an x86 server
The answer should make reference to:
    Typical processors e.g. Xeon
    Chipsets – difference from desktop PC and laptops
    The core hardware
    Integrated peripherals
    Features not found on a typical desktop PC e.g. temperature
       monitoring, server health monitoring, server virtualisation
4. Name the major manufacturers of x86 server products and list their
   entry level products
   Justify their interest in the x86 server market
   Discuss the size of this market and the market share of the major
5. Energy costs in data centres is now a major issue – calculate the cost
   of running a server for a year and compare this with the purchase
   price of the server
   Discuss the features of a modern server which optimise features such
   as performance/ Watt

6. Companies such as Dell offer server products with GPGPU support for
   use as powerful Graphics workstations – Explain how this products
   work and list typical applications

7. Virtualisation is becoming an issue for data centres – explain the
   nature of server virtualisation and storage virtualisation
8. Review the impact of ‘the cloud’ on server provision

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                                                        Revision Server Technology 2

Outline Answers
Topic - Servers
Advantages of Client-Server configuration
Deploying servers in a network brings many advantages
     The configuration is structured
     It is obvious who is in charge – the server administrator
     Security is easier to establish – individual PC firewalls, anti-virus software can be
       updated via the server
     Backup is centralised and can be automated
     Users can be given appropriate access to system resources
     Resources can be shared according to the individual PC user’s privilege
     Maintenance is simplified e.g. application inventories can be centralised, user logs
       can be monitored

Servers become essential to the efficient running of the organisation as mission critical files
are stored on the servers

The server becomes a key feature in the network and RAS kicks into action – Reliability,
Accessibility and Serviceability

A server outage may mean that users cannot logon, cannot access their data

An extreme client-server configuration is called thin client. The server holds and executes all
programmes, stores all data whereas the client is merely a networked graphical workstation.
There is no need to upgrade the client or provide virus protection since it is only a display
system controlled by network packets from the Server. This is gaining popularity again
described as a Virtual Desktop – client can be any hardware including a smartphone – the
server runs multiple Windows sessions (one for each client)

In the Department of Eng & Tech a different client-server model is used. The clients are
standard PCs and are loaded with the various application packages from MS Office to CAD
packages. The programmes execute on the client PC but most user files are stored in the
user areas on the server. When a user logs off only the files on the server are stored.

A2. RAS Reliability, Availability and Serviceability

The failure of an individual PC in a network will reduce the productivity of the individual user
a PC – this reduction in productivity may be important

The failure of a server in a single server environment may be critical in that a small
organisation may be in serious financial problems, if no users can access central account
documents – server reliability is thus critical

The reliability of servers can be improved compared to a desktop PC by better mechanical
construction, better electrical layout, better thermal design, redundant components such as
power supplies, disks etc etc

Availability is reflected in the up-time of a server – 5 9s is often quoted 99.999% availability
which will relate to features such as the ability to recover from an error such as a serious
application crash or the communication features which deal with high network traffic

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                                                        Revision Server Technology 3

Serviceability relates to the ability to swap a failed component such as a disk – increasingly
this is supported by hot swap components – a disk can be powered down and replaced – a
feature of SATA and SAA disk sub-systems

Traditional server used ‘heavy metal technology’ derived from mainframe technology. The
systems were expensive and used operating systems such as UNIX. These systems require
an expert team to support server operation
For simple applications such as file and print servers these systems were overkill and it was
obvious that a low cost PC with an upgraded Windows operating system could provide most
facilities at lower cost and could be maintained by an administrator with enhanced PC
maintenance skills

This was the start of the x86 server market which now is the first choice for many
organisations – the x86 server market accounts for 50% of server sales by value and the vast
majority of servers numerically (98%)

Processors – Intel have a range of processors designated for use in servers – the Xeon range
e.g. there are Xeon chips which are similar to say core i7-9xx processors except two of these
processors can be installed on a server motherboard using a server chipset. Server
applications/ OS generally make better use of a multicore/ HyperThreaded/ multiprocessor
environment. Hardware features supporting virtualisation are provided and are increasingly

Server chipsets also support buffered ECC memory, SATA and SAS hard disks with Raid and
hot swap

Modern server motherboards can support critical monitoring of power and even provide on
board support for the hypervisor which facilitates server virtualisation – a single server can
support multiple operating systems (e.g. Windows and Linux) carefully partitioned so that if
one OS crashes the other can continue processing

The big three in the x86 (or x64) server market are HP, IBM and Dell – HP sell the most
servers numerically but HP and IBM have similar server revenues

This is a large market with the attraction that it is less cut throat than the desktop/ laptop

Entry level prices are quite cheap (similar to well specified PCs) but nearly all users will add
significant extra memory/ disks/ backup facilities/ etc

The cost of running a Server can be significant
For example a server rated at 1 kW will use 1 times 24 times 365 kWhr per year = 8760 kWhr
at 10p a kWhr this is 876 pounds and this doesn’t take air conditioning costs into account !

Modern servers are carefully monitored to power down under low loads by reducing
processor clock frequency etc thus optimising performance/Watt – in addition the latest
processors can rapidly respond to demand by over-clocking selected cores – this optimises
the server performance to match user demands -

Server virtualisation also reduces the number of servers by allowing multiple OSs to execute
on the same server

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                                                     Revision Server Technology 4

   The concept is quite simple – GPGPU products from say nVidia are readily available and
   are very well suited to graphics processing for complex CAD, modelling etc

   So a low cost Server can be converted into a powerful workstation by adding GPGPU
   cards into, say, the PCI bus

   The GPGPU cards are developed for the PC industry e.g. games PCs and so the
   development costs for GPGPU products suitable for workstations are low

   Software support now extends to integrate with the x86 range of software

   The classical approach to running two separate applications which require different OSs
   is to have two servers e.g. a Windows server to run IIS and a Linux server to run Apache

   √ applications can be optimised for the individual hardware

   ! two lots of hardware to support
   ! applications may not require all the computing performance of the platform

   Solution – use virtualisation which effectively allows two operating systems to co-exist on
   the same hardware
    The OSs are effectively partitioned from each other – ideally if Windows crashes
        Linux will be unaffected
    There will be a performance overhead but if each server is only 30% loaded this may
        be marginal
    Virtualisation can be entirely a software based function but with modern processors
        support for virtualisation is built into the hardware of the processor
    Although most people think about using virtualisation to run different operating
        systems on the same hardware, features such as networking can be virtualised – the
        network facilities as seen by an OS or application can be entirely virtual – the
        mapping to the real networking hardware is achieved through a virtualisation layer –
        reconfiguring the network interface for an application is managed by the
        virtualisation layer

Internet based server provision can be in many forms – a remote server which you physically
rent and upload files to/ a remote storage environment which is secure and expands to
meet archive requirement/ virtual server provision where you rent e.g. a virtual Windows
server which is located in a remote data centre
The selling point is often elastic computing - you rent what you currently need

Some users are unhappy because they lose control of the hardware and network outages
can be serious

10/09/2011 1:27 PM G South 89351b0b-cfd4-4036-a7ed-18199f925f6f.doc

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