Query about rlink

The example I gave for 3 sites is for a single RVG, so this shows one data set, which is replicated to different DR servers, so:

Data is written at Prod and
  Prod replicates to DR1
  and Prod replicates to DR2

There is no replication between DR1 and DR2, but the rlinks are in place to replicate between DR1 and DR2, but they are not active - rlinks are only active between a primary and an secondary and are not active between secondaries.  You don't have to create an rlink pair between the 2 DR servers, but if you didn't then if you made DR1 the primary as in the 2nd example, then data would ONLY be replicated to Prod1 and not to DR2 which maybe what you want as you may not have a network link between DR1 and DR2, but if you did want to replicate between DR1 and DR2 in the event that Prod failed and DR became the primary, you would need to create an rlink pair between DR1 and DR2
 

The norm is to have one or more RVGs each with 2 sites (1 primary and 1 secondary) and not many customers have 3 sites (2 secondaries) as it is expensive to have 3 copies of the data.  When you have mulitple RVGs these are all independent.  So you have the normal situation of 2 site RVGS (each RVG has 1 secondary) and so all rlinks are normally active.  If the IPs you have shown are virtual IPs so that the virtual IPs could reside on the same host, this makes no difference to VVR, the 2 RVGs are still independent and both will normally replicate at the same time.

So you could have both RVGs on the same pair of 2 servers (if IPs .5 and .6 both reside on Pri1 and .8 and .9 reside on DR2):

Host Pri1:            Host DR2:
data_rvg1             data_rvg1
192.168.12.5  ====>   192.168.12.8

data_rvg2             data_rvg2
192.168.12.6  ====>   192.168.12.9

Or you could have 2 primary servers replicating to the same "DR3" server (if IPs .8 and .9 both reside on DR3)

Host Pri1:            Host DR3:
data_rvg1             data_rvg1
192.168.12.5  ====>   192.168.12.8

Host Pri2:
data_rvg2             data_rvg2
192.168.12.6  ====>   192.168.12.9

Host Pri1:            Host DR3:
data_rvg1             data_rvg1
192.168.12.5  ====>   192.168.12.8

Host Pri2:            Host DR4:
data_rvg2             data_rvg2
192.168.12.6  ====>   192.168.12.9

These 3 combinations all work the same in respect of VVR - the 2 RVGs (data_rvg1 and data_rvg2) replicate independently.

Mike