Resizing Disks in Disk Groups

The RESIZE clause of ALTER DISKGROUP enables you to perform the following operations:

Resize all disks in the disk group
Resize specific disks
Resize all of the disks in a specified failure group

If you do not specify a new size in the SIZE clause, then Oracle ASM uses the size of the disk as returned by the operating system. The new size is written to the Oracle ASM disk header and if the size of the disk is increasing, then the new space is immediately available for allocation. If the size is decreasing, rebalancing must relocate file extents beyond the new size limit to available space below the limit. If the rebalance operation can successfully relocate all extents, then the new size is made permanent, otherwise the rebalance fails.

The following example resizes all of the disks in failure group failgrp1 of disk group data1. If the new size is greater than disk capacity, the statement fails.

Example 4-7 Resizing disks in disk groups

ALTER DISKGROUP data1 
     RESIZE DISKS IN FAILGROUP failgrp1 SIZE 100G;