dynamic load balancing on web server systems l.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Dynamic Load Balancing on Web-server Systems PowerPoint Presentation
Download Presentation
Dynamic Load Balancing on Web-server Systems

Loading in 2 Seconds...

play fullscreen
1 / 18

Dynamic Load Balancing on Web-server Systems - PowerPoint PPT Presentation


  • 180 Views
  • Uploaded on

Dynamic Load Balancing on Web-server Systems. Valeria Cardellini, Michele Colajanni, and Philip S. Yu Presented by Sui-Yu Wang. Distributed Web-server System. Consisting of multiple Web-server hosts, distributed on LANs and WANs Spread incoming requests among these servers

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Dynamic Load Balancing on Web-server Systems' - Ava


Download Now An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
dynamic load balancing on web server systems

Dynamic Load Balancing on Web-server Systems

Valeria Cardellini, Michele Colajanni, and Philip S. Yu

Presented by Sui-Yu Wang

distributed web server system
Distributed Web-server System
  • Consisting of multiple Web-server hosts, distributed on LANs and WANs
  • Spread incoming requests among these servers
  • Each server can respond to any request
  • Successful load-balancing approaches make the distributed system appear as a single host
distributed web server architectures
Distributed Web-server Architectures
  • Client-based
    • Web clients
    • Client-side proxies
  • Web-server based
    • DNS-based
    • Dispatcher-based
    • Server-based
dns based approach
DNS-based approach
  • Architecture transparency
  • DNS has limited control on requests reaching the Web cluster
    • TTL
  • Scheduling algorithms
    • Constant TTL
    • Adaptive TTL
scheduling algorithms
Scheduling algorithms
  • Constant TTL algorithms
    • System-stateless algorithms
      • Round-Robin DNS
    • Server-state-based algorithms
    • Client-state-based algorithms
      • Hidden load weight
        • Multitier round-robin policy
      • Consider relative server-to-client topology and client-to-server link latency
      • Network proximity information, round trip delays
    • Server-and client-state-based algorithms
scheduling algorithms7
Scheduling algorithms
  • Adaptive TTL algorithms
    • Select server similar to the hidden load weight algorithms
    • Assign appropriate TTL
    • Can scale from LANs to WANs
dispatcher based approach
Dispatcher-based Approach
  • Centralized request scheduling
    • Packet rewriting
      • Single-rewriting
      • Double-rewriting
    • Packet forwarding
    • HTTP redirection
packet forwarding
Packet forwarding
  • Network Dispatcher
    • Works with LANs and WANs
    • Client and server transparent
  • ONE-IP Address
    • Routing-based dispatching
    • Broadcast-based dispatching
    • No dynamic load-balancing based on server load
http redirection
HTTP redirection
  • Centralized dispatcher
  • Does not require modification of packet IP address
  • Server-state based dispatching
  • Location-based dispatching
server based approach
Server-based approach
  • Two-level dispatching
  • No centralized dispatching
  • HTTP redirection
  • Packet redirection
    • Static routing
    • Load-balancing
performance evaluation
Performance evaluation
  • Exponential model: the number of page requests per session and the time between two page requests from the same client were assumed to be exponentially distributed
performance evaluation18
Performance evaluation
  • Client load variability is represented by some heavy-tailed function