HP XP P9500 Storage - Manual (Page 44)

number of ports for a Continuous Access Journal Z system is two. To determine the required number
of initiator and RCU target ports.
1.
Measure IOPS for your production system. When you measure write-workload, IOPS is also
provided. (See
“Measuring write-workload” (page 23) ).
2. Using peak IOPS and the maximum IOPS for a VSP Fibre Channel port (70,000), calculate
the number of ports your Continuous Access Journal Z system requires. Peak IOPS / 70,000.
For example: if your performance monitoring software shows peak IOPS at 280,000, then the
calculation would be: 280,000 / 70,000 (max. IOPS per port) = 4. This example shows that four
ports are required for the measured peak IOPS.
On setting up ports
The following tips are provided to help you design your port configuration:
•
When new data exists, the initiator port on the local system sends informational commands
to the secondary RCU target port.
•
The remote system initiator port sends journal query commands to the local RCU target port.
When new data exists in the primary system, the data is sent through these ports — that is,
from primary side RCU target port(s) to secondary system initiator port(s).
An example configuration could consist of the following:
◦ Two initiator ports on the local side, with two matching RCU target ports on the remote
side
◦ Four initiator ports on the remote side, with four matching RCU target ports on the local
side.
◦ An initiator port on one side must have an RCU target port on the other side.
•
If your system will support a disaster recovery failover/failback environment, initiator and
RCU target ports should be configured the same on the primary and secondary storage systems.
•
Up to eight paths can be established in both directions. HP strongly recommends that you
establish at least two independent data paths to provide hardware redundancy.
•
Host paths cannot be connected to an initiator port. However, they can be attached to RCU
target ports.
NOTE: One or more initiator ports must be configured on both the primary and secondary storage
subsystems before you can add the secondary storage system and create Continuous Access Journal
Z volume pairs. A minimum of two initiator ports on both the primary and secondary storage
subsystems (configured on separate fibre channel CHAs) is highly recommended for redundancy.
Distances supported for Fibre Channel type, number of switches
Fibre Channel multimode or single-mode optical fiber cables are required on primary and secondary
systems. The type of cable and number of switches depends on the distance between primary and
secondary sites.
•
0 to 0.5 km: multimode optical shortwave fiber cables are required.
•
0.5 km to 1.5 km (1,640 to 4,920 feet): multimode shortwave Fibre Channel interface cables
are required; one switch is required, two maximum.
•
1.5 km to 10 km: single optical long wave fiber cables are required.
•
10 km to 30 km (6.2 to 18.6 miles): single-mode long wave Fibre Channel interface cables
are required; one switch is required, two maximum.
•
Greater than 30 km (18.6 miles): approved third-party channel extender products and
telecommunications lines are required.
44 Planning the data path