Article number
Affected Versions
Source Hypervisor
Target Hypervisor

How to Determine the Amount of TCP Sessions Zerto Creates for Replication

Viewed 559 times


For network load/security reasons, an Administrator would want to know how many TCP connections the VRA creates during its replication process.


Here are all VRA connections it creates during the replication process:

ZVM -> VRA control - 1
ZVM -> VRA checkpoints - 1

The VRA -> VRA connections are a full graph – all are connected to all.

For each pair of VRAs:
VRA1 -> VRA2 control - 1
VRA2 -> VRA1 control - 1

If there's a replicating volume between VRA1 -> VRA2 then will be also 8 data sockets (another 8 if there's also replication between VRA2 -> VRA1).
So the formula is:
Number of VRAs - N
Number of pairs - P (=N*(N-1)/2)
Number of replicating pairs - R (R<=P*2)

Number of TCP connections = 2N+2P+8R
Where 2N are connections inside the LAN and 2P+8R are over WAN.