Filter
Top Products
74 IBM System Storage DS6000 Series: Copy Services with IBM System z
This section discusses the parameters that can be passed to FlashCopy when using the DS
CLI and what the results are. Figure 9-1 summarizes the parameters and the corresponding
DS CLI commands. When FlashCopy receives these parameters, the following actions result:
freeze: Consistency Group FlashCopy
With the DS CLI, it is possible to establish a Consistency Group by using the -freeze
parameter and identifying all FlashCopy pairs and target volumes belonging to it.
tgtpprc: establish target on existing Metro Mirror source
When this option is selected, the target volume can be, or can become, a source volume
for a Metro Mirror or Global Copy relationship.
tgtoffline: permit FlashCopy to occur if target volume is not online for host access
When setting up the relationship, a verification is done to see whether the target volume is
online or offline. This parameter only applies to CKD volumes. Table 9-4 summarizes the
actions that result, depending on the target volume status.
Table 9-4 Resulting actions when the tgtoffline parameter is used
tgtinhibit: Inhibit writes to target volume
If FlashCopy is active, writes to the target volume are not allowed (inhibited).
record: change recording
Activating the option
change recording during setup of a FlashCopy enables subsequent
refreshes to the target volume. To do so, a second bitmap is created for the source
volume, which keeps track of all writes to the source. This bitmap can later be used to
refresh the target by only copying the updates from the source to the target.
persist: persistent FlashCopy
The FlashCopy relationship will continue to exist until explicitly removed by an interface
method. If this option is not selected, the FlashCopy relationship will exist until all data has
been copied from the source volume to the target.
nocp: full volume background copy
With the parameter nocp it is possible to indicate whether the data of the source volume
will be copied to the target volume in the background or not. If -nocp isn’t used, a copy of
all data from source to target takes place in the background. With -nocp selected only
updates to the source volume will cause writes to the target volume—this way the
time-zero data can be preserved.
seqnum: sequence number for FlashCopy pairs
A number that identifies the FlashCopy relationship. Once used with the initial mkflash
command, it could be used within subsequent commands to refer to multiple FlashCopy
relationships.
source:target: identification of source volume and target volume
fast: reverse FlashCopy before background copy finished
Status of target
volume in z/OS
Permit FlashCopy
to occur if target
volume is online
Resulting action
Volume is online Not selected FlashCopy definition is not possible
Volume is online Selected FlashCopy definition is queued until target
volume goes offline
Volume is offline Selected or not
selected
FlashCopy will be started immediately