HP 3PAR Operating System Software - Manual (Page 17)

Figure 2 Bidirectional 1-to-1 Remote Copy
N-to-1 Configuration
An N-to-1 remote-copy configuration is composed of multiple remote-copy pairs. A maximum of
four primary storage systems use the same backup storage system.
NOTE: Because the backup system participates in one remote-copy pair for each primary system,
a backup system with one or two primary systems needs only two controller nodes. A backup
system with three or more primary storage systems must have four or more controller nodes.
You can set up N-to-1 remote copy with up to four unidirectional or bidirectional remote-copy pairs,
as long as the remote target system has the minimum number of nodes required to support the
number of source systems.
M-to-N Remote-Copy Configurations 17