What do I need to know before increasing my reserved capacity on a mirrored pair volume?

Typically, you should increase reserved capacity when you receive a warning that the reserved capacity for a mirrored pair is becoming full. You can increase reserved capacity only in increments of 8 GiB.

For asynchronous mirroring operations, reserved capacity is typically 20 percent of the base volume. Choose a larger capacity for reserved capacity if one or both of these conditions exist:

• You intend to keep the mirrored pair for a long period of time.
• A large percentage of data blocks will change on the primary volume due to heavy I/O activity. Use historical performance data or other operating system utilities to help you determine typical I/O activity to the primary volume.

You can increase the reserved capacity for a mirrored pair by performing one of these actions:

• Adjust the capacity percentage for a mirrored pair volume by selecting Storage > Pools and Volumes Groups and then clicking the Reserved Capacity tab.
• Create a new volume using free capacity that is available on a pool or volume group.

  If no free capacity exists on any pool or volume group, you can add unconfigured capacity in the form of unused drives to a pool or volume group.