Sizing Your Content Store

The content store is used by Content Manager to store all IBM® Cognos® BI information that is visible in, or managed through, IBM Cognos Connection or your third-party portal. The content store is at the heart of IBM Cognos BI, and must have sufficient resources to operate effectively. To maximize IBM Cognos BI performance and scalability, ensure that your content store has the resources required to ensure that it does not become a bottleneck.

The size of the IBM Cognos BI content store you need depends on the number and size of the IBM Cognos BI items, such as reports, packages, and schedules, that you will create and store. Over time, as users create more items, the amount of space needed for the content store typically increases.

When determining the amount of space to allocate for your content store, consider the following:

Example - Estimating Content Store Size

The size of an empty content store hosted in a Microsoft SQL Server database is approximately 2 to 3 Mb. Depending on your size allocation strategy, this may vary for other supported databases.

The number of concurrent users affects the size of the content store because temporary disk space is allocated to serve report run requests, even if the requests are not saved.

Out of 50 concurrent users, approximately 25% will be executing reports and 75% will be viewing saved outputs. As a result, approximately 12.5 of the 50 users will be running reports (50 concurrent users * 0.25 executing reports = 12.5 concurrent users).

The following table provides an example of how to estimate the size of the content store you need.

*As a rule of thumb, the ratio of named to active to concurrent users is 100:10:1. However, the ratio varies with the environment. For more information, see Estimating Concurrent Users.

Table 1. Example of factors that affect the size of a content store

Factor

Number

Estimate of content store requirements (Kb)

Named users

1000*

not applicable

Active users

250*

not applicable

Concurrent users (temp space requirements)

50*

5,000,000

Saved reports: 1-10 pages (2 per user for Public and Myfolder copies at 340 Kb per report)

1001

340,340

Saved reports: 10-100 pages (9 per user for 4 Public and 5 Myfolder copies at 440 Kb per report)

5,004

2,201,760

Saved custom views: 1-100 rows (3 per user, all Myfolders at 250 Kb per view)

3,000

750,000

Saved custom views: 100-1000 rows (8 per user, all Myfolders at 350 Kb per view)

8,000

2,800,000

Folders (Public and Myfolders)

1,025

500

Framework Manager models

15

100,000

Framework Manager models (tables)

25

-

Framework Manager models (query subjects)

50

-

Schedules (day and week)

175

5,000

Empty content store

--

3,000

Database transaction logs

--

3,000,000

Total

--

14,200,600

For more information about capacity planning, visit the IBM Cognos Customer Center ( (http://www.ibm.com/software/data/support/cognos_crc.html).