Scalable System Design

8/19/2019 Scalable System Design

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A presentationon

Scalable System Design1

Presented by:

Md. Hasan Ansar i

MSCS/071/655


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Inroduction

Scalability is ability of a system, network, or process tohandle a growing amount of work in a capable manner.

For example, it can refer to the capability of a system toincrease its total output under an increased load whenresources (typically hardware) are added.

It is a highly significant issue in electronics systems,

databases, routers, and networking. A system, whoseperformance improes after adding hardware,proportionally to the capacity added, is said to be ascalable system.

!


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"easuring the scalability of a system#

$here hae also been different perceptions on how tomeasure scalability% maximum number of simultaneous users supported by

the system or maximum transactions processed per unit of time by the

system.

For example, the re&uirement could say that the systeminitially should be able to support ' simultaneous users, but it should be scalable enough to support up to 'simultaneous users.


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"easuring the scalability of a system

• $he throughput of thesystem usually iincreasesinitially as the system isexposed to an increasing

load.

• After a certain limit thethroughput of the system

decreases from *neepoint.


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"easuring the scalability of a system'

$his may happen due tomany reasons

like the system may befeeling the scarcity ofhardware resources

After adding hardwareknee point is shifted.


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+calable +ystem esign -atterns

/ptimi0e Algorithm

Add ardware

Introduce -arallelism

/ptimi0e ecentrali0ation2ontrol +hared 3esources


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/ptimi0e Algorithm

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$he key to the solution is to identify the areas those can beoptimi0ed for performance when the input load increases.

$he aim is to identify tasks which can be completed in ashorter period to sae processing time. $his shall result inoerall throughput improement of the system by allowingthe saed 2-5 time to be allocated for growing work.

$hese areas can in some cases be identified by carrying acode walkthrough to identify areas where smarteralgorithms can help improing the performance.


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/ptimi0e Algorithm

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If code walkthrough does not help, then certain tools can be usedto identify the areas which are consuming most of the timeduring processing.

$hese tools (like I7" 3ational 8uantifier) help identifying theareas (functions) which are eating up most of the 2-5 time.

5sing an alternate algorithm which shall result in keeping theend result same but complete the same task in a shorter duration.

*nown 5ses% 3unning time of Insertion sort is / (n9n), whilethat of 8uick sort is /(n lg n). ence, &uick sort scales better with n as compared to insertion sort as depicted in the Figure .


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/ptimi0e Algorithm:


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Add ardware1

$he key to the solution is to identify the hardware resources which are becoming scarce for the system. $he scarce hardwareresources can be identified by using resource monitoring tools(like prstat;top).

/nce the scarce hardware resources are identified, the next stepis to add them in efficient &uantity. $he hardware resources can be added to the same existing physical hardware or it may beadded as a new physical hardware.

Adding hardware to the existing physical node will result in whatis commonly known as


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Add ardware11

*nown 5ses%

Adding 3A" to the existing machine incase it isdetected that the system re&uires more memory.

Adding a separate machine to a cluster in case it isfound that all the existing machines in the cluster are

being utili0ed to their full capacity.


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Introduce -arallelism1!

ow can a system maintain its performance withincreasing input load>

+ystem that does not want to deteriorate itsperformance when the load increases and has thecapability to split the work in to pieces which can be completed simultaneously.


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Introduce -arallelism1#

$he key to a scalable design is to process multipletransactions in the system simultaneously. $hesystem should do parallel processing in order tomaintain the throughput with the increasing load.

$he work should be diided in to pieces that can bedone simultaneously so as to do more processing in

the same time.


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Introduce -arallelism1


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Introduce -arallelism1'

-arallelism can come in different forms%

? A system can hae multiple threads (Intra?processscalability)

? /r, it can hae multiple processes (Inter?processscalability)

? /r, a system can hae mix of both of the aboe(ybrid scalability) in order to process multipletransactions simultaneously.


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Introduce -arallelism1

*nown 5ses%

Apache?$omcat cluster haing multiple $omcatnodes @ each one of them processing

$$- re&uests independently. oweer, thesedifferent instances may be talking to the samedatabase instance.


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7roadband 3emote Access +erer

A 2ase +tudy in epal $elecom14

A broadband remote access server (BRAS) routestraffic to and from broadband remote access deicessuch as digital subscriber line accessmultiplexers (+BA") on an Internet serice

proiderCs (I+-) network. 73A+ can also be referred toas a Broadband Network Gateway (BNG).

$he 73A+ sits at the core of an I+-Cs network, andaggregates user sessions from the access network. It isat the 73A+ that an I+- can inDect policy managementand I- 8uality of +erice (8o+).


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7roadband 3emote Access +erer

16


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7roadband 3emote Access +erer1:

$he specific tasks include% Aggregates the circuits from one or more link access deices

such as +BA"s

-roides layer ! connectiity through either transparent bridging or --- sessions oer Ethernet or A$" sessions

Enforces &uality of serice (8o+) policies

-roides layer # connectiity and routes I- traffic throughan Internet serice proiders backbone network to theInternet


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7roadband remote access serer

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A +BA" collects data traffic from multiple subscribers into acentrali0ed point so that it can be transported to a switch orrouter oer a Frame 3elay, A$", or Ethernet connection.

$he router proides the logical network termination. 2ommonlink access methods include --- oer Ethernet (---oE), ---oer A$" (---oA, bridged ethernet oer A$".

$he 73A+ is responsible for assigning network parameters suchas I- addresses to the clients.

$he 73A+ is also the interface to authentication, authori0ationand accounting systems.


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3eferences

!1


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!!

$hanks

8ueries>

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Scalable System Design