- Lecturer

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.
• 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
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 one
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)
• Performance of all other peripherals
• Network throughput, etc
Clients
• 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
processing and/or data.
• Applications that run on user computers
Clients are Applications
• Rely on servers for
– Files, Devices, or Processing power
• Example: E-mail client
Types of Dedicated Servers
From A to Z
•
•
•
•
•
•
•
Application Servers
Audio/Video Servers
Chat Servers
Fax Servers
FTP Servers
Groupware Servers
IRC Servers
•
•
•
•
•
•
List Servers
Mail Servers
News Servers
Proxy Servers
Telnet Servers
Web Servers
File Server Architecture
FAT CLIENT
Database server architecture
Thinner
clients
DBMS only on
server
Client Server Computing
• Advantages
– Simple
– Easy to design/maintain
– 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
More of the code runs on the server
The network interaction is minimized
Application
Client
Server
Client vs Server
Thin 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
Protocols used
–
–
–
–
–
VNC
NFS
Secure Shell
RDP
X11
Fat client
• Advantages
–
–
–
–
–
Fewer server requirements
Offline working
Better multimedia performance
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
Client (dumb) - Server Model
One tier model
Server
Client
Presentation Logic
Network
Application Logic
DBMS
True Client-Server Model
Two tiers model
Server
Client
Application Logic
Presentation Logic
Network
DBMS
Three tiers Model
Server
Client
Application Logic
Application Logic
Network
DBMS
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 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.
• 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
interoperate with other software, without
requiring the user to understand and code the
low-level operations required to achieve
interoperability
• 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 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
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
– 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 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)
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
– 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
– 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 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
Sequential Applications
Sequential Applications
Parallel Applications
Parallel Applications
Parallel Applications
Parallel Programming Environment
Cluster Middleware
(Single System Image and Availability Infrastructure)
PC/Workstation
PC/Workstation
PC/Workstation
PC/Workstation
Communications
Communications
Communications
Communications
Software
Software
Software
Software
Network Interface
Hardware
Network Interface
Hardware
Cluster Interconnection Network/Switch
Network Interface
Hardware
Network Interface
Hardware
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
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
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)
• Folding@home (abbreviated as FAH or F@h)
• Einstein@Home
• GIMPS – Great Internet Mersenne Prime Search
• LHC@home
Next
• Web Architectures