HP XP P9500 Storage - Manual (Page 50)

If the difference between the two is insignificant, for example, 1ms : 5 ms, initial copying is
allowed to run at the specified pace.
To determine Round Trip Time value
The value of Round Trip Time = round trip time between MCU-RCU x 2(*) + initial copy response time (ms)
(*) A data transfer between main and remote system involves two response sequences in one command issuance.
Therefore, you need to double the round trip time.
•
For the “round trip time” in the formula, contact HP Technical Support, or use a ping
command. If you do not use lines between the main system and remote system, specify
“1”.
•
The "initial copy response time" in the formula is the response time required for multiple
initial copy operations. You can use the following formula to get the initial copy response
time. To get the time, you should use the following: the initial copy pace, the max number
of maximum initial copy VOLs , the speed of the line between main and remote system ,
and the number of lines.
Initial copy response time (ms) = (1[MB] / “Speed of line between MCU-RCU[MB/ms](*1)”) x (“initial copy
pace”(*2) / 15) x (“max number of maximum initial copy VOLs (*3)” / “Number of lines between MCU-RCU”(*4))
(*1) When you connect MCU with RCU without lines, specify 0.17[MB/ms] in “Speed of line
between MCU and RCU”.
(*2) For “initial copy pace” in the formula above, see the table below.
(*3) For “maximum number of maximum initial copy volumes,” use the value set up per storage
system. The default is 64.
(*4) Even if “Max number of maximum copy VOLs” / “Number of lines between MCU-RCU”
is larger than 16, specify “Max number of maximum initial copy VOLs” / “Number of lines
between MCU-RCU” as 16.
Table 24 Initial copy pace used for response time calculation
Initial, Update Copy in Progress Initial Copy Only in
Progress Interface
When Initial Copy Pace Specified
at the Time of Pair Creation is 9
to 15 When Initial Copy Pace Specified
at the Time of Pair Creation is 1
to 8
8 User-specified value between 1
and 8 User-specified value Business
Continuity
Manager
8 User-specified value between 1
and 8 User-specified value Remote Web
Console
8(*) 15(*) PPRC command
(TSO/ICKDSF)
and CU
emulation is
2105 or 2107
(*) When a PPRC command (TSO/ICKDSF) is used and the CU emulation type is 2105 or 2107, the initial copy
pace specified is invalid. Therefore, the fixed value will be set.
50 Configuration operations