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Chapter 7. FlashCopy options 59
7.5 Remote FlashCopy
There are command interfaces (see Figure 7-8 on page 61) which are able to manage a
FlashCopy relationship at a remote site. The commands can be issued from the local site and
they are then transmitted over the Metro Mirror or Global Copy links. This eliminates the need
for a network connection to the remote site solely for the management of FlashCopy.
The FlashCopy source volume at the remote site must be the secondary volume of the Metro
Mirror or Global Copy pair.
Figure 7-6 Remote FlashCopy
Figure 7-6 illustrates this capability. In this figure, the Metro Mirror (or Global Copy) secondary
and the FlashCopy source are the same volume—they are shown as two separate volumes
for ease of understanding.
7.6 Persistent FlashCopy
With this option the FlashCopy relationship continues until explicitly removed, that is, until the
user terminates the relationship using one of the interface methods. If this option is not
selected, the FlashCopy relationship will exist until all data has been copied from the source
volume to the target.
7.7 Data set FlashCopy
Data set FlashCopy is supported with z/OS and OS/390® volumes only. This option can be
invoked using the interfaces that support data set FlashCopy as per Figure 7-8 on page 61.
The following are characteristics of data set FlashCopy:
The data set source and target volumes need not be the same size.
The location within the target volume need not match the location within the source.
Data sets can be copied onto the same source volume.
Multiple relationship FlashCopy is supported with Data set FlashCopy.
If a Data set FlashCopy relationship, established with DFSMSdss and with the
nocopy
parameter, is deleted, DADSM (the Direct Access Device Space Management component
of z/OS) will start a background copy prior to deleting the data set. When all data is copied
successfully, the FlashCopy relationship will end and the data set will finally be deleted.
Global
Copy
primary
secondary
Global
Copy
source
target
FlashCopy
Metro
Mirror
Metro
Mirror
Remote site
Local site