Objectives of knowledge management

 multi- tenancy
arrangement rather than a 
 single- tenancy
arrangement. This is similar to the situation with the shared server or dedi-
cated server we discussed earlier for web hosting. An example of this in practice is shown in 
Box 3.3.
 Multi- tenancy SaaS
A single instance of a 
web service is used 
by different customers 
(tenants) run on a single 
server or load- balanced 
across multiple servers. 
Customers are effectively 
sharing processor, disk 
usage and bandwidth 
with other customers.
 Single- tenancy SaaS
A single instance of 
an application (and/or 
database) is maintained 
for all customers (tenants) 
who have dedicated 
resources of processor, 
disk usage and 
bandwidth. The single 
instance may be load- 
balanced over multiple 
servers for improved 
performance.
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Part 1
Introduction
Box 3.3
Is my SaaS single- tenancy or multi- tenancy?
Smoothspan (2007) has estimated the level of multi- tenancy for different web services, 
which is also dependent on the number of seats or users per server. He estimates that 
in 2006 Salesforce was running 40 Dell PowerEdge servers with 6,700 customers (ten-
ants) and 134,000 seats. This is equivalent to 168 tenants per server, and 3,350 seats 
per server! Although this figure suggests the disadvantage of multi- tenancy, he also 
estimates that there is a 16:1 cost advantage of multi- tenant over single tenant.
An example of a consumer SaaS, word processing, would involve visiting a website which 
hosts the application rather than running a word processor such as Microsoft Word on your 
local computer through starting ‘Word.exe’. The best- known consumer service for online 
word processing and spreadsheet use is Google Docs (http://docs.google.com) which was 
launched following the purchase in 2006 by Google of start-up Writely (www.writely.com). 
Google Docs also enables users to view and edit documents offline, through Google Gears, an 
open- source browser extension. ‘Microsoft Office Live’ is a similar initiative from Microsoft.
Google Apps enables organisations to manage many of their activities. The basic service is 
free, with the Premier Edition, which includes more storage space and security, being $50 per 
user account per year.
A related concept to web services is