For the procedures for swapping disks, see "5.3.4 Disk Swap" when using GDS Management View, or see "D.8 sdxswap - Swap disk" when using a command.
This sub-section describes important points about disk swap.
Swapping Disk Unit
After excluding the target disk unit to be swapped from GDS, swap the disk unit with the same procedure as the disk unit not registered to GDS. For how to swap it, see the manuals of the server, OS, and disk unit.
Hot swap
For hot swap, swap a disk with the following procedures:
Excluding a disk from GDS
Excluding the disk from OS
Swapping a disk unit
Including the disk to OS
Including the disk to GDS
For "2. Excluding a disk from OS" and "3. Swapping a disk unit," see the manuals of the server, OS, and disk unit.
Physical Disk Size
Physical disk swap cannot be performed using a physical disk whose size is smaller than the original disk size.
Disk Label
If you swap a disk that is registered with a class, the disk label type of the swapped disk must be identical to that of the class. If the disk label type is not identical or no disk label has been created, use the format(1M) command, etc. to either change the disk label or create one before performing "Restore Physical Disk" on GDS Management View or executing the sdxswap -I command. The disk label type of physical disks can be viewed by the verify menu of the format(1M) command. The disk label type of a class can be viewed in the LABEL field displayed with the sdxinfo -C -e label command.
Physical Disks That Cannot Be Swapped
Physical disk swap 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 swap 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 swap by making any one of the following configuration changes.
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.
When performing disk swap for a single disk, add the single disk and another unused disk to a new mirror group, and complete volume synchronization copying.
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 swap, disks can be swapped without stopping active applications.
Swapping Physical Disks in a Cluster System
If physical disks that are registered with the resource database were swapped, after physical disk restoration (or the sdxswap -O command) is completed, perform automatic resource registration regardless of the class types. This is required for changing volume names set to the disk label of original disks to those of replacing disks that are registered with the PRIMECLUSTER resource database. If automatic resource registration is not performed, a message indicating a disk unit connection error may be output or failover may occur when nodes are started.
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 "Appendix D 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 swap 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 swap 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 "5.3.4 Disk Swap" and "D.8 sdxswap - Swap disk." After removing the shadow disk, perform disk swap referring to the manual of the disk unit's copy function.
Swapping Physical Disk when the Proxy Volume is in a Mirroring Configuration
When the proxy volume is in a mirroring configuration and it is in a Join state, since the resynchronization copying is not performed after the disk which configures the proxy volume is swapped, the slice of the proxy volume on the swapped disk will become INVALID.
For the operation on Part and Rejoin the proxy object, see "D.14 sdxproxy - Proxy object operations."
