HP XP7 Storage - Manual (Page 46)

Cnt Ac-S Z pairs Pair statuses
All = Suspend Some = Duplex, some = Suspend All = Duplex
Cnt Ac-S Z: Suspend Cnt Ac-S Z: Suspend Cnt Ac-S Z: Suspend
Cnt Ac-S: PSUS Cnt Ac-S: PSUS Cnt Ac-S: PSUS All = PSUS
Cnt Ac-S Z: Suspend Cnt Ac-S Z: Cnt Ac-S Z:
- RAID Manager: Duplex/Suspend - RAID Manager: Duplex
- BCM: Suspend - BCM: Suspend
Error reporting communications
Error reporting communications (ERC) transfers information between host processors at the local
and remote sites. It is a critical component of a disaster recovery effort.
You can configure ERC using channel to channel communications, NetView technology, or other
inter-connection technologies depending on your installation requirements and standards. Continuous
Access Synchronous Z does not provide ERC between the local and remote sites.
•
When Continuous Access Synchronous Z is used as a disaster recovery tool, ERC is required
to ensure effective recovery operations.
•
When Continuous Access Synchronous Z is used as a data migration tool, ERC is
recommended.
•
When a pair is split due to an error condition, the primary system generates sense information
that results in an IEA491E system console message. This information should be transferred to
the remote site using ERC for effective disaster detection and recovery.
Data path requirements and configurations
A data path must be designed to adequately manage all possible amounts of data that could be
generated by the host and sent to the P-VOL and S-VOL. This topic provides requirements and
planning considerations for the following key elements of the data path:
•
“Bandwidth requirements” (page 46)
•
“Fibre Channel requirements” (page 46)
•
“Supported data path configurations” (page 47)
•
“Ports” (page 49)
Bandwidth requirements
Sufficient bandwidth must be present to handle data transfer of all workload levels. The amount
of bandwidth required for your Continuous Access Synchronous Z system is based on the amount
of I/O sent from the host to the primary system. You determine required bandwidth by measuring
write-workload. Workload data is collected using performance monitoring software. Consult your
HP account team for more information.
Fibre Channel requirements
The primary and secondary system must be connected using multimode or single-mode optical
fibre cables.
•
For distances between .5 km to 1.5 km, one switch is required, but you can use a maximum
of two switches.
•
For distances up to 1.5 km (4,920 feet), multimode shortwave Fibre Channel interface cables
are used.
46 Planning for Continuous Access Synchronous Z