HP XP Business Copy Software - Manual (Page 127)

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NOTE: If an external volume is specified as a FlashCopy Version 2 T-VOL, be careful about the setting of
the time of path blockade watch, which is the time from when the external disk array is disconnected to
when the path is blocked. If the time of path blockade watch set for the T-VOL is longer than the time of the
MIH (Missing Interrupt Handler) timer which is set for the S-VOL on the host side, MIH may occur on the
S-VOL and the processing may end abnormally when the external disk array is powered off or when
failures occur.
If the host I/O to the S-VOL is more important than the host I/O to the T-VOL, make sure that the time of
path blockade watch for the T-VOL is smaller than the time of the MIH timer which is set for the S-VOL. In
this way, the FlashCopy Version 2 pair will be suspended when the T-VOL is blocked because of the path
blockade watch, therefore the host I/O to the S-VOL can be maintained.
If the host I/O to the T-VOL and the T-VOL data are more important than the host I/O to the S-VOL, use the
default setting of the path blockade watch for the external volume that is to be specified as the T-VOL.
The following table shows whether you can perform Reverse Restore on the S-VOL or the T-VOL of a
FlashCopy® Mirror Version 2 pair to which attributes are set by other solutions.
Table 63 Whether Reverse Restore Can be Used When FlashCopy® Mirror Version 2 Volume is Used as
Volume of Other Solutions
Using Compatible Mirroring for IBM FlashCopy Version 2 Host Commands
FlashCopy Mirror Version 2 supports both DFSMSdss commands and TSO PPRC commands to enable you
to perform FlashCopy Mirror Version 2 operations from the zSeries and S/390 host system. The operation
system versions that support FlashCopy Mirror Version 2 are OS/390 V2R10 and z/OS V1R0 and higher.
An appropriate PTF is necessary for each.
This user guide does not provide complete instructions for using commands from the host system. For
detailed information on using DFSMSdss and TSO PPRC commands, please refer to the following IBM user
documents.
• z/OS® DFSMSdss Storage Administration Reference (SC35 0424)
• z/OS® DFSMS Advanced Copy Services (SC35 0428)
• z/OS® DFSMSdfp Advanced Services (SC26-7400)
DFSM Command Supported by Compatible Mirroring for IBM FlashCopy Version 2
This section only describes how to use the representative DFSMSdss commands related to FlashCopy Mirror
Version 2. For detailed information on using DFSMSdss commands, please refer to the following IBM user
document: z/OS DFSMSdss Storage Administration Reference (SC35 0424).
Solutions Attribute FlashCopy Mirror Version 2
S-VOL T-VOL
Volume Retention
Manager
Protect This attribute cannot be set. This attribute cannot be set.
Read only OK OK
Read/Write OK OK
Volume Security Security setting that disables
the volume for use as S-VOL
This setting can be made. This setting cannot be made.
Universal Volume
Manager
External storage This setting cannot be made. NO