HP StorageWorks XP Remote Web Console Software User Manual
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SCP Time of TrueCopy for Mainframe and the state-change-pending time of FlashCopy Mirroring
V2 are same. To determine the SCP Time of TrueCopy for Mainframe, take into account the fact
that if you change the SCP Time setting by the CU Option dialog box, the state-change-pending
time of FlashCopy Mirroring V2 will change. For more information on state-change-pending time
of FlashCopy Mirroring V2, see the HP XP24000/XP20000 for FlashCopy Mirroring Software
User's Guide.
The Maximum Initial Copy Activities: allows you to specify the number of volumes on which copy
operations can be performed at the same time from 1 to 16 volumes for the selected CU . When
you set Disable for Maximum Initial Copy Activities (CU) option on the System Option dialog box,
you cannot specify this option. Even if you set a value larger than the setting for Maximum Initial
Copy Activities on the System Option dialog box, the priority is given to Maximum Initial Copy
Activities on the System Option dialog box.
Configuring and Maintaining Your TrueCopy for Mainframe Environment
Optimizing TrueCopy for Mainframe Operations and Storage System Performance
All TrueCopy for Mainframe operations result in increased utilization of the XP disk array's channel
resources because of the additional write (remote copy) operations to the secondary volumes. The
TrueCopy for Mainframe update copy mode (synchronous or asynchronous) determines exactly
how the remote copy operations will impact storage system performance as follows:
•
Synchronous copy mode (TrueCopy for Mainframe Synchronous) has an additional effect on
storage system performance: increased service and disconnect time for write I/Os to TrueCopy
for Mainframe M-VOLs due to the delay between channel-end and device-end. The length of
this delay increases as the distance between the M-VOL and R-VOL increases, so that the
longest delay occurs when the main and remote volumes are the maximum distance apart.
•
Asynchronous copy mode does not create any delays which occur during the TrueCopy for
Mainframe Synchronous operation due to the distance between the P VOL and S VOL. However,
the response to the host is delayed compared with non paired volumes because write I/Os
to the P-VOL are written as a side file in cash in an asynchronous copy mode. The only
performance concerns for TrueCopy for Mainframe Asynchronous are:
◦
To ensure that adequate cache resources are available for sidefiles which are used to
store the recordsets at both the MCUs and RCUs.
◦
To ensure that sufficient MCU-RCU paths are defined for copy operations.
In addition to the TrueCopy for Mainframe update copy mode, several other factors can also affect
HP disk array performance. You can optimize both the TrueCopy for Mainframe operations and
the I/O performance of the storage systems by analyzing workloads and addressing system-level
conditions (for example, number of remote copy connection paths) which can affect storage system
performance.
You can also control the impact of TrueCopy for Mainframe operations on storage system
performance by selecting the appropriate RCU options for each MCU and the appropriate update
copy mode (synchronous or asynchronous) and pair options for each TrueCopy for Mainframe
pair. In addition, you can upgrade the TrueCopy for Mainframe hardware components and/or
adjust the configuration of the components to improve storage system performance under a wide
range of operating conditions.
“Optimizing TrueCopy for Mainframe Operations and HP disk
lists some of the conditions which affect storage system performance
and provides recommendations for addressing these conditions.
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Performing TrueCopy for Mainframe Configuration Operations