IBM Advanced SerialRAID Adapters SA33-3285-02, User Manual

Page: 179 / 531

Using the ssa_make_copy Command to Create a RAID Copy from a RAID-1 or
RAID-10 Array
Figure 22 shows a volume group that contains one physical volume: hdisk1. This hdisk
is a RAID-1 array.
The ssa_make_copy command checks whether the hdisk is either a RAID-1 or a
RAID-10 array. If the array is neither of these types, the command displays a warning,
then stops.
If the hdisk is of the correct type, the ssa_make_copy command finds a suitable copy
disk drive for RAID-1 or suitable copy disk drives for RAID-10. It then couples the copy
disk drive, or drives, to the parent volume group, and runs the copy operation (see
Figure 23).
When the copy operation has completed and the copy array has been uncoupled, the
fast-write cache (if present) is temporarily disabled, and data is flushed to the physical
disk drives. The ssa_make_copy command then forces the parent volume group to
synchronize. The synchronize operation flushes all data from memory to disk, and stops
all I/O operations.
The command uncouples the copy disk drive from the parent hdisk, clears the PVID of
the copy disk drive, restarts the I/O operations, and reenables the fast-write cache.
Figure 22. A Volume Group the Contains One Physical Volume
Figure 23. A Copy Disk Drive Coupled to the Parent hdisk
Chapter 7. Copying Data from Arrays and from Volume Groups
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