HP XP P9500 Storage - Manual (Page 26)

with the Required option specified, the main system detects DFW OFF at the R-VOL and suspends
the pair. The default for Continuous Access Synchronous Z pairs created using PPRC commands
is Not Required, therefore they are not suspended when DFW to R-VOL is blocked.
The DFW to R-VOL setting does not affect M-VOL I/O performance. If one side of cache is closed
due to a remote system failure, the copy operation still uses DFW. The difference between not
required and required is that new pairs cannot be established with the required option when one
side of RCU cache is closed. In this case, the Add Pair operation fails (This restriction applies only
when the CU emulation type of RCU is 3390).
Using an earlier model storage system
•
If you are creating a Continuous Access Synchronous Z pair using an earlier model disk array
at the remote site (such as the XP12000/XP10000 Disk Array), make sure that both the main
and remote disk array have a unique 5–digit serial number. It is possible that a serial number
overlap could occur. If you have two systems with the same serial number, contact your HP
account team for assistance.
•
When you connect the storage systems with the following combinations, the range you can
specify for each model is restricted.
◦ P9500 Disk Array and XP12000/XP10000 Disk Array
When you connect P9500 Disk Array and XP12000/XP10000 Disk Array, you can specify
the ranges in the following table.
Table 10 Range you can specify when connecting P9500 Disk Array and XP12000/XP10000
Disk Array
XP12000/XP10000 Disk Array
*1*3
P9500 Disk Array
*1
Restriction item
From 1A to GR From 1A to GR Port number
From 00:00 to 3F:FF From 00:00:00 to 00:3F:FF LDKC
*2
:CU:LDEV
*1 It does not affect to the value whether the model connects as MCU or RCU.
*2 LDKC number is applied only for P9500.
*3 If you connect a P9500 with an XP12000/XP10000 Disk Array, or a P9500 with an XP24000/XP20000
Disk Array, contact HP Technical Support for further information on the XP12000/XP10000 Disk Array and the
XP24000/XP20000 Disk Array DKCMAIN program version.
Enabling R-VOL Read, other system options
You can tailor P9500 systems to enable the R-VOL Read option and other functions. System option
modes related to Continuous Access Synchronous Z and PPRC operations are shown in the table
below.
(For more information on I/O to the R-VOL, see “Planning I/O to the R-VOL” (page 31) .
P9500 option modes can only be changed by your HP representative. Since they are set to their
default values at installation, discuss changes with your HP team.
Table 11 Option modes for Continuous Access Synchronous Z
Description Option mode
R-VOL read-only function (RCU only). 20
Selects function of CRIT=Y(ALL) or CRIT=Y(PATHS). 36
•
Mode 36 ON: CRIT=Y(ALL) => equivalent to Fence Level = Data.
• Mode 36 OFF: CRIT=Y(PATHS) => equivalent to Fence Level = Status.
26 Planning for Continuous Access Synchronous Z