Sybase 12.4.2 manual Disk striping option, Disk striping hints, 444

DROP DBSPACE

Balancing I/O

Disk striping option

This section explains how you can use the option Adaptive Server IQ provides to do disk striping, without using third party software. If you already have a disk striping solution through third party software and hardware, you should use it instead.

Turning disk striping The syntax you use to turn disk striping on or off is: on or off

SET OPTION "PUBLIC".DISK_STRIPING = { ON OFF }

The default is ON for UNIX systems, and OFF for Windows NT systems. When disk striping is ON, incoming data is spread across all dbspaces with space available. When disk striping is OFF, dbspaces (disk segments) are filled up from the front on the logical file, filling one disk segment at a time.

As with all PUBLIC options, you must disconnect and then reconnect in order for the change to take effect.

When disk striping is on, you cannot drop dbspaces with the

command. Since dbspaces are dropped as they are empty from last to first, and with this strategy dbspaces are filled partially in a more distributed manner, it is unlikely the dbspaces will be empty. If you want to be able to drop dbspaces, you should set DISK_STRIPING to OFF.

Disk striping hints

Here are several different ways to think about distributing space on a large disk drive, for example 9GB:

1Use different segments in different databases.

2Mix them into the usage list with segments from different disk drives in between.

3For the best multiuser performance, set your operating system or disk array to the maximum stripe size it supports.

Here is a good example:

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