IBM Metro Mirror (PPRC)
Metro Mirror or PPRC (Peer-to-Peer Remote Copy) is a synchronous copy services solution, support throughout the ESS, DS6800 and DS8000 model ranges.
Metro Mirror is used primarily as part of a business continuance solution for protecting data against disk storage system loss or complete site failure.
With Metro Mirror, each write operation to the "primary" disk subsystem will be replicated real-time to a secondary disk subsystem in another location. The primary disk subsystem will only complete its write operation after the secondary controller has acknowledged successful receipt of the data. Not only will this introduce overhead for the primary disk subsystem controllers, but it will also introduce a delay for each write operation. The extra time needed increases as longer distances are involved, limiting synchronous solutions to about 300 kilometers (186 miles).
IBM has a summary of their business continuity solutions on:
IBM Business Continuity Solutions
The IBM Copy Services data sheet can be found at:
In our products
IntelliMagic Vision can be used in the planning phase of Metro Mirror (PPRC) in z/Series environments to identify the bandwidth required between your IBM subsystems (and thus the number of Fibre links), and it can be used to identify whether there are very busy volumes that might not be able to tolerate the additional delay inherent to synchronous copy services solutions.
Once Metro Mirror (PPRC) is implemented, IntelliMagic Vision can continue to be used to track the growth of the bandwidth requirements. IntelliMagic Vision also shows the impact of PPRC on the disk response time (disconnect time), giving you a better understanding of the response time impact. IntelliMagic Vision does support the PPRC-specific link statistics recorded by the ESS-800, DS6800 and DS8000 such that you see track actual link delay and traffic, including incoming PPRC traffic on secondary devices.
IntelliMagic Direction can be used to model PPRC performance, but before and after it is implemented. With IntelliMagic Direction you can predict the PPRC impact on response time.