HP XP7 Storage - Manual (Page 75)

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ANTRQST Macro
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z/VM CP
CAUTION: Observe the following cautions about releasing relationships:
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A time-out may occur when more than 100 FlashCopy relationships are released at the same
time. To avoid timeouts, divide the tasks into small groups and release relationships at intervals
of about 5 seconds per 100 relationships.
It is recommended that the number of relationships per volume should not exceed 4000, even
though the maximum allowable number of relationships per volume is 65,534. The Withdraw
command deletes relationships in the volume all at once, so if you execute the Withdraw
command when the number of relationships per volume is large and the MP operating rate
of the MP blade is high, a time-out may occur.
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If an MIH occurs and cancellation of a relationship ends abnormally, the relationship remains
in effect. If this occurs, re-execute the Withdraw command.
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When you cancel a large number of relationships, the processing for canceling relationships
takes a long time and might cause an MIH to occur. Therefore, you should complete background
copy operations before you cancel relationships.
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To prevent an MIH from occurring, reduce the number of relationships to be canceled with
one command to 4000 or less. This also applies when you execute the INIT, SCRATCH, or
DELETE commands, which cause the Withdraw command to be issued during processing.
Using PPRC TSO to release Compatible FlashCopy relationships
The FCWITHDR command can be used to release relationships established for copy operations set
either in COPY or NOCOPY mode.
CAUTION: If you use the FCWITHDR command a single time when deleting numerous relationships,
a timeout may occur with the host. Therefore, use the FCWITHDR command repetitively when
releasing numerous relationships. Also, after you execute the FCWITHDR command the first time,
wait for a period of time before you execute the command again. For example, if you execute the
FCWITHDR command one time when deleting more than 100 relationships, wait for approximately
5 seconds until you execute the command again.
The following table shows the parameters you can use with the FCWITHDR command when you
release Compatible FlashCopy relationships:
Table 42 Parameters for the FCWITHDR command (Compatible FlashCopy)
Description Value Parameter
Specify the number (device address) of the S-VOL on which you want
to perform FCWITHDR command. Source device number. SDEVN
Specify the number (device address) of the T-VOL on which you want
to perform FCWITHDR command. Target device number. TDEVN
Specify the number (device address) of the device on which you want
to perform FCWITHDR command with ACTION parameter. Device number. DEVN
Specifies the Cnt Ac-S Z source device number (device address). Cnt Ac-S Z source device number
Use this parameter when REMOTE is YES.
The relationships established on the volume specified as the copy
source by SDEVN are withdrawn. The relationships are withdrawn YES DDSW
after the contents of the volume specified as the copy target by TDEVN
are fixed.
Releasing Compatible FlashCopy relationships 75