Flashcopy Consistency Groups; Remove Local Flashcopy Using Rmflash - IBM System storage DS6000 Series Redbook
Copy services with ibm system z
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Also See for System storage DS6000 Series:
- Redbooks (406 pages) ,
- Attachment manual (298 pages) ,
- Introduction and planning manual (119 pages)
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Example 9-8 rmflash command to create new background copy
#--- Example 1
rmflash -dev IBM.1750-13ABC2A -quiet -cp 0001:0101
Date/Time: July 11, 2005 11:21:05 AM CEST IBM DSCLI Version: 5.0.3.134 DS: IBM.1750-13ABC2A
CMUC00143I rmflash: Background copy process for FlashCopy pair 0001:0101 successfully started. The persistent relationship will not be
removed
In the example presented in Example 9-8, create new background copy of a persistent
FlashCopy relationship, the existing FlashCopy relationship 0001:0101 is used to create a
new background copy.
Remove local FlashCopy using rmflash
The command rmflash can be used to remove a FlashCopy relationship. Unlike other
commands, it doesn't return an error if the request runs for a FlashCopy relationship that
doesn't exist.
In scripts it should always be used with the -quiet parameter to avoid the confirmation
prompt. See Example 9-9.
Example 9-9 rmflash command example
#--- Example 1
rmflash -dev IBM.1750-13ABC2A -quiet 0001:0101
Date/Time: July 11, 2005 11:21:39 AM CEST IBM DSCLI Version: 5.0.3.134 DS: IBM.1750-13ABC2A
CMUC00140I rmflash: FlashCopy pair 0001:0101 successfully removed.
In Example 9-9, the existing FlashCopy relationship 0001:0101 is removed.
9.4.3 FlashCopy Consistency Groups
Typically, large applications such as databases have their data spread across several
volumes. In order to create a consistent copy or backup, a FlashCopy of all the volumes
should be done at exactly the same point-in-time. FlashCopy Consistency Groups are
designed to achieve this exact purpose.
Creating FlashCopy Consistency Groups using mkflash
Use the mkflash command with the -freeze parameter to create a FlashCopy Consistency
Group. This command causes the DS6000 to briefly prevent I/O to the volumes in the
Consistency Group. During this time, any I/O that comes from the host will be returned with a
long busy error, which the host bus adapter will automatically retry. However, if the I/O is
frozen for an extended period of time, there will be application errors on the host. For this
reason, the Consistency Group should be unfrozen as quickly as possible.
Example 9-10 illustrates the creation of a FlashCopy Consistency Group that contains two
FlashCopy pairs.
Example 9-10 Creating FlashCopy Consistency Groups
dscli> mkflash -dev IBM.1750-7506571 -freeze 1500-1501:1502-1503
Date/Time: October 24, 2005 3:37:49 AM PDT IBM DSCLI Version: 5.0.5.6 DS: IBM.1750-7506571
CMUC00137I mkflash: FlashCopy pair 1500:1502 successfully created.
CMUC00137I mkflash: FlashCopy pair 1501:1503 successfully created.
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IBM System Storage DS6000 Series: Copy Services with IBM System z
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