Segregating Database Components
To achieve best performance, it is usual to place the components of a database, such as the redo log, table spaces and indexes, on different disks. Using ISP, this can be accomplished by using the Annotation Service feature, which allows you to define new characteristics and then assign these to your disks.
Note
The Annotation Service is accessed by selecting a disk in the VERITAS Enterprise Administrator, and then selecting Actions > Annotate Disks. This feature is not available from the command line.
The Annotation Service can be used in conjunction with volume rules to reserve disks for particular volumes. By tagging disks with a suitable attribute name and value such as reserved_for and redo_log, you can use a confineto rule to ensure that the volume for a redo log is only allocated space from those disks:
confineto "reserved_for"="redo_log"
Conversely when creating volumes that are not to be used for the redo logs, you can specify an exclude rule:
exclude "reserved_for"="redo_log"
This technique allows you to share appropriately tagged disks among a set of volumes of the same type. For example, if you specify the same confinement rule when creating several redo log volumes in a storage pool, those volumes share the disks that are reserved for that purpose.
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