IBM Tivoli Monitoring > Version 6.3 Fix Pack 2 > Installation Guides > Installation Guide > Tivoli Data Warehouse solutions > Plan considerations for the Tivoli Data Warehouse

IBM Tivoli Monitoring, Version 6.3 Fix Pack 2


Understanding the disk requirements for your database

Consider the factors in this section when designing a disk subsystem to support your database processing.

The following table provides some example sizes for a database:


Database size examples

  Number of disks to use
Absolute minimum disks Small RDBMS Small and safe RDBMS Large RDBMS
Operating System 1 1 1 + mirror 1
Paging and RDBMS code Use above 1 1 + mirror 1
RDBMS data 1 1 1 + mirror 8
RDBMS indexes 1 1 1 + mirror 6
RDBMS temp Use above 1 1 + mirror 6
RDBMS logs 1 + mirror 1 + mirror 1 + mirror 2
Database data 12 GB 24 GB 48 GB 108+ GB
Number of disks 5 7 12 24

The Absolute minimum disks column specifies the minimum number of disks for an RDBMS. In this column, the index and temporary space is allocated onto one disk. While not an ideal arrangement, this might work in practice because databases tend to use indexes for transactions or temporary space for index creation and sorting full table scan large queries, but not both at the same time. This is not a recommended minimum disk subsystem for a database, but it does have the lowest cost.

The Small RDBMS column represents a minimum disk subsystem, although there might be limits in I/O rates because of the data being placed on only one disk. Striping the data, indexes, and temporary space across these three disks might help reduce these I/O rate limits. This disk subsystem arrangement does not include disk protection for the database or other disks (apart from the mandatory log disk protection for transaction recovery).

The Small and safe RDBMS column adds full disk protection and can withstand any disk crash with zero database downtime.

The Large RDBMS column represents a typical size database for a database subsystem. Disk protection is not included in these sizings but can be added to increase the stability of the database.


Parent topic:

Plan considerations for the Tivoli Data Warehouse

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