IBM Netfinity ServeRAID-4H Ultra160 User Reference page 125

target partitions, and then creates a snapshot-like backup of the source data on the
target partition. The target partition is available instantly for read access.
Note: To create the backup copy, the following must be true:
v The size of the target partition must be equal to or larger than that of the
source partition.
v The partition type must be the same on the source and target partitions.
When issuing the FlashCopy function, you must specify either the FlashCopy
backup or FlashCopy nobackup functions to create a backup.
The FlashCopy backup function sets up a link between the source and target
drives. This link creates a backup of the source data on the target drive. After the
link is set up, a background copy operation is immediately initiated to copy all the
data from the source drive to the target drive. After the background copy operation
completes, the link between the source and target drives is dissolved.
The FlashCopy nobackup function also sets up a link between the source and
target drives. Unlike the FlashCopy backup function, after the FlashCopy
nobackup link is set up, no background copy operation immediately takes place.
The background copy operation waits until the data on the source logical drive
changes. When a change to the data on the source drive occurs, the backup of the
source logical drive data gets copied to the target logical drive. Then, the new data
gets written to the source logical drive. This FlashCopy nobackup link exists until
you dissolve the link by issuing a FlashCopy stop.
Note: You have instant read access to the target partition after a FlashCopy
backup or FlashCopy nobackup is issued.
Important
Before using FlashCopy, consider the following:
v Normal I/O functions can be performed on the source partition while the FlashCopy
operation is in progress. If you are performing a FlashCopy backup, do not write to the
target partition until the FlashCopy backup process is complete.
If you are performing a FlashCopy nobackup, do not write to the target partition at all.
v You can have up to four FlashCopy relationships active at a time.
v The source and target drives must be on the same controller.
v There is no limit on source and target partition size.
v When FlashCopy completes, the data on the target partition will be an exact image of the
data on the source partition at the time FlashCopy was issued.
v The target partition must be at least the same size as the source partition. For optimal
space usage, the FlashCopy target partition should be the same size as the source
partition.
v You can use the noprompt option to run some FlashCopy functions without receiving
any interactive prompts.
v Both the source and target drives must be either spanned arrays or non-spanned arrays.
v If the source and target drives are spanned arrays, they must have the same number of
sub-arrays.
v If the source and target drives are part of a spanned array, there can be only one
partition for each logical drive on that spanned array.
The following information shows you how to use the FlashCopy function.
Chapter 11. Using utility programs
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