ATI : Arsitektur Server

anton@ukdw.ac.id

Server

• A server consists of one or more computers that response and process requests from one or more client machines. machines.

• A server is typically designed with some redundancy in power, network, computing and file storage.

Server type

• a server’s processing performance is limited

by, among other things, microprocessor

performance

• Multiprocessor servers fall into one of two • Multiprocessor servers fall into one of two

major classes:

– Tightly-coupled or Symmetrical Multiprocessor

– Loosely-coupled or Asymmetrical Multiprocessor

Tightly coupled (SMP)

SMP characteristics

• By symmetrical, which mean that each processor can access each resource of the system; that is, any processor can play any role in the system.

• An SMP functions under the control of oneoperating system, which manages all system operating system, which manages all system resources

• SMP is using threads

• OS has to support multiprocessor, memory sharing, and threads

– Ex: Windows 2000, Windows Server 2003, etc

Software execution model for

tightly coupled

1 core proc Multi-core proc

Loosely Coupled

Software execution model for

loosely coupled

Server’s Performance Measurement

• Number of Processors

• Memory capacity

• Throughput of the connections between

subsystems (BUS)subsystems (BUS)

• Performance of all other peripherals

• Network throughput, etc

• A client is an individual user's computer or a user application that does a certain amount of processing on its own.

• It also sends and receives requests to and get response from one or more servers for other

Clients

response from one or more servers for other processing and/or data.

• Applications that run on user computers

• Rely on servers for

– Files, Devices, or Processing power

• Example: E-mail client

Clients are Applications

Types of Dedicated Servers

• Application Servers

• Audio/Video Servers

• Chat Servers

• List Servers

• Mail Servers

• News Servers

From A to Z

• Chat Servers

• Fax Servers

• FTP Servers

• Groupware Servers

• IRC Servers

• News Servers

• Proxy Servers

• Telnet Servers

• Web Servers

File Server Architecture

FAT CLIENTFAT CLIENT

Database server architecture

Thinner Thinner clientsclients

DBMS only on DBMS only on serverserver

Client Server Computing

• Advantages

– Simple

– Easy to design/maintain

– Commonly used– Commonly used

– Data consistency

• Disadvantages

– Bottleneck on servers

– High specification server

Generic Client/Server Architecture

Multiple

server

• Service disediakan oleh beberapa server

• Contoh: sebagian besar layanan web komersial diterapkan melalui server fisik yang berbeda

• Untuk: kehandalan, unjuk gigi

• Server menggunakan replikasi atau database terdistribusi

Client/Server Models • Fat clients

– The bulk of the application is running on the client

– The client knows how the data is organized and where it is

– Different clients access the same applications different ways

• Fat servers– The server more complicated

– The clients are less complex – The clients are less complex

– More of the code runs on the server

– The network interaction is minimized

ServerClient

Application

Client vs ServerThin Client Thick Client

Contoh Thin Client:

• VNC client (Virtual Network Controller)

• VNC is remote control software which allows you to view and fully interact with one computer desktop

Thin client

• Introduced by Oracle in 1993

• Depends heavily on servers

• Low-cost for clients

• Focuses on presentation layers

• Portable clients• Portable clients

• Protocols used– VNC

– NFS

– Secure Shell

– RDP

– X11

Fat client

• Advantages

– Fewer server requirements

– Offline working

– Better multimedia performance

– More flexibility– More flexibility

– Using existing infrastructure

• Disadvantages

– Complexity in maintenance

– Security issues

– Higher cost

Interaksi client-server

Types of Architectures

• One Tier Architecture

• Two Tiers Architecture

• Three Tiers Architecture

• N-Tiers Architecture

ClientServer

Client (dumb) - Server ModelOne tier model

Presentation Logic

Application Logic

DBMS

Network

True Client-Server ModelTwo tiers model

ClientServer

Presentation Logic Network

Application Logic

DBMS

Three tiers Model

ClientServer

Network

Application Logic

DBMS

Application Logic

Presentation Logic

N-Tier architecture (on Web)

C/S Interaction

Karakteristik Client-Server

• Service : Menyediakan layanan terpisah yang berbeda

• Shared resource : Server dapat melayani beberapa client pada saat yang sama dan mengatur pengaksesan Resourcepengaksesan Resource

• Asymmetrical Protocol : antara client dan server merupakan hubungan one-to-many.

• Mix-and-match : tidak tergantung pada platform

• Encapsulation of service : message memberitahu server apa yang akan dikerjakan

Karakteristik Client-Server (2)

• Transparency Location : proses server dapat ditempatkan pada mesin yang sama atau terpisah dengan proses client. Client/server akan menyembunyikan lokasi server dari client.

• Message-based-exchange : antara client dan server berkomunikasi dengan mekanisme pertukaran

• Message-based-exchange : antara client dan server berkomunikasi dengan mekanisme pertukaran message.

• Scalability : sistem C/S dapat dimekarkan baik vertikal maupun horisontal

• Integrity : kode dan data server diatur secara terpusat, sedangkan pada client tetap pada komputer tersendiri

Middleware

• Software which allows an application to interoperateinteroperate with other software, without requiring the user to understand and code the low-level operations required to achieve interoperabilityinteroperability

• Types of Middleware:– RPC

– Publish/Subscribe (Push & Pull Technology)

– Message oriented middleware

– Object Request Broker middleware

– Database Middleware

Push Technology – Push Mail

Pull Technology - SMTP

Pull Technology – RSS Reader

P2P behind the scene

• Today’s clients can perform more roles than just forwarding users requests

• Today’s clients have:

– more computing power– more computing power

– more storage space

• As the Internet usage grow, more and more PCs are connecting to the global net

• Most of the time PCs are idle

• Thin client � Fat client

Technology Transition

The Client/Server Model

The Peer-to-Peer Model

Peer-to-Peer Computing

• P2P does not distinguish clients and servers

– Instead all nodes are considered peers

– May each act as client, server or both

– Node must join P2P network

• Registers its service with central lookup service on • Registers its service with central lookup service on

network, or

• Broadcast request for service and respond to requests

for service via discovery protocol

– Examples include Napster and Gnutella

P2P is decentralization

• A key feature of peer-to-peer networks is

decentralization.

• This has many implications:

– robustness: handal– robustness: handal

– availability of information: selalu ada & tersebar

dimasing2 client

– fault-tolerance tends to come from redundancy

=> satu down yg lain bisa handle

– and shared responsibility: tugas dibagi

Why P2P?

• Information - Hard to find, impossible to

catalog and index all of the information

• Bandwidth - Hot links get hotter– Makin bagus informasi, makin laris dan makin tak

terbendung

Makin bagus informasi, makin laris dan makin tak

terbendung

– Makin banyak juga yg “memilikinya” dan tersebar

dimana-mana

• Computing resources - Heavily loaded nodes

get overloaded, idle nodes remain idle

Dangers and Attacks on P2P

• Poisoning (files with contents different to its description)

• Polluting (inserting bad packets into the files)

• Defection (users use the service without sharing)

• Insertion of viruses (attached to other files)• Insertion of viruses (attached to other files)

• Malware (spy originally attached to the files)

• Denial of Service (slow down or stop the network traffic)

• Filtering (some networks don’t allow P2P traffic)

• Identity attacks (tracking down users and disturbing them)

• Spam (sending unsolicited information)

P2P Computing Applications

• File sharing

– Improves data availability

– E.g., Napster, Gnutella, BitTorrent, KaZaA

• Collaborative environments• Collaborative environments

– For remote real-time human collaboration.

– Instant messaging, virtual meetings, shared whiteboards, teleconferencing, tele-presence.

– E.g.: talk, IRC, ICQ, AOL Messenger, Jabber, MS Netmeeting, Skype

What is Cluster ?

• A cluster is a type of parallel and distributed processing system, which consists of a collection of interconnected stand-alone computers cooperatively working together as a single, integrated computing resource.

• A cluster:

– generally 2 or more computers (nodes) connected together– generally 2 or more computers (nodes) connected together

– in a single cabinet, or physically separated & connected via a LAN

– appear as a single system to users and applications

– provide a cost-effective way to gain features and benefits

Clustered Systems Usage

– Usually sharing storage via a storage-area

network (SAN) via LAN

– Provides a high-availability service which

survives failuressurvives failures

– Some clusters are for supercomputing

– Cluster server is for load-balancing system

– Cluster systems usually more tightly coupled

than grid computing

Cluster Architecture

Sequential Applications

Parallel Applications

Parallel Programming Environment

Cluster Middleware

(Single System Image and Availability Infrastructure)

Sequential ApplicationsSequential Applications

Parallel ApplicationsParallel Applications

(Single System Image and Availability Infrastructure)

Cluster Interconnection Network/Switch

PC/Workstation

Network Interface Hardware

Communications

Software

PC/Workstation

Network Interface Hardware

Communications

Software

PC/Workstation

Network Interface Hardware

Communications

Software

PC/Workstation

Network Interface Hardware

Communications

Software

Active/Passive – Asymetric cluster

http://networksandservers.blogspot.com/2011/09/failover-clustering-iv.html

Active/Active – Symetric cluster

http://networksandservers.blogspot.com/2011/09/failover-clustering-iv.html

What is a Grid?

• Grid computing is the collection of computer

resources from multiple locations to reach a

common goal (usually single task!)

• The difference from cluster is: grids tend to be • The difference from cluster is: grids tend to be

more loosely coupled, heterogeneous, and

geographically dispersed.

• Using parallel processing and programming

Why do we need Grids?

• Many large-scale problems cannot be solved

by a single computer

• Globally distributed data and resources

• Independent computing• Independent computing

Grid Computing

Grid Architecture

Windows Azure Grid Example

Example of Grid Computing

• SETI (Search for Extraterrestrial Intelligence)

@Home project

• BOINC (Berkeley Open Infrastructure for Network

Computing)Computing)

• Folding@home (abbreviated as FAH or F@h)

• Einstein@Home

• GIMPS – Great Internet Mersenne Prime Search

• LHC@home

Next

• Web Architectures