PRIMECLUSTER Global Disk Services Configuration and Administration Guide 4.1 (Solaris(TM) Operating System)

A.2.16 Swapping Physical Disks

For the procedures for swapping disks, see "Disk Swap" when using GDS Management View, or see "sdxswap - Swap disk" when using a command.
This sub-section describes important points about disk swapping.

Physical Disk Size

Physical disk swapping cannot be performed using a physical disk whose size is smaller than the original disk size.

Physical Disks That Cannot Be Swapped

Physical disk swapping cannot be performed for a disk where the only valid slice (in ACTIVE or STOP status) within the volume exists.

For example, it is impossible to perform disk swapping if:

• The volume is in a group to which only one disk is connected.

• The volume is on a single disk that is not connected to a group.

In these situations, it will be possible to perform disk swapping by making any one of the following configuration changes.

1. If the disk to be swapped is connected to a mirror group, add a new disk to the mirror group and complete volume synchronization copying normally.

2. When performing disk swapping for a single disk, add the single disk and another unused disk to a new mirror group, and complete volume synchronization copying.

3. Remove the existing volume from the disk to be swapped.
   Before removing the volume, back up volume data if necessary.

When data on a disk to be swapped is valid, for example when conducting preventive maintenance, a or b is recommended. Here, if the disk unit supports hot swapping, disks can be swapped without stopping active applications.

Swapping Physical Disk Registered with Shadow Classes

When swapping disks of shadow disks registered with GDS Snapshot shadow classes, the shadow disks must be removed with the relevant GDS Snapshot command first. For details on GDS Snapshot commands, see "Command Reference."

The subsequent operations vary depending on whether the disk units to be swapped are registered with disk classes.

• If the disk is registered with a disk class

  After removing the shadow disk, perform disk swapping in the domain managing the disk class using the relevant procedure.
  An error in a disk may not cause failures on both the related SDX and shadow objects. Even if only either of the objects fails, shadow disk removal and disk swapping using the relevant procedure are both necessary.

  
  

• If the disk is not registered with a disk class

  In this situation, the disk to be swapped is a copy destination of the disk unit's copy function.
  It is not necessary to perform GDS operations described in "Disk Swap" and "sdxswap - Swap disk." After removing the shadow disk, perform disk swapping referring to the manual of the disk unit's copy function.