1. Clustered Web Server Model1 2
File
Server 3
Cache
Dispatcher
(Front End)
Manager N
Object
Store
Web
Clients
Server
Nodes

2. Server Parameters Num server nodes Mem cache size Disk cache size
Cache replacement policy for each (LRU, LFU, SIZE, DUAL)
Comm. latency
Cache consistency
Dispatch policy (DNS, RR, Redirect, Load)
Request distribution policy (requests, bw, conns, affinity, ...)
Server bandwidth
Per-request bandwidth
BW scaling model

3. Performance Metrics Load balancing
requests
bytes
bandwidth
connections
clients
Relative improvement versus RR, Rand, etc
Cache performance
document hit rate
byte hit rate
Comm. overhead
Avg response time
Avg inflation factor
Others...