Using the CARP protocol for redundancy on SolidServer 8.2.3a, shows latency when testing failover

Products

• VMware NSX

Issue/Introduction

The CARP protocol switches the MAC address from Server1 on HostA to Server2 on HostB.  When this happens, a delay can be observed before VM1 on HostC is aware of this change. This behavior causes a temporary outage when Server1 fails over to Server2 or vice versa.

Certain products such as SolidServer Efficient IP (EIP) use CARP protocol for HA failover. When the primary node is down, secondary sends GARP packet with Ethernet Header showing source MAC of secondary VM. The ARP header shows VIP MAC. 

Cause

Due to VIP MAC not being sent in GARP packets under the Ethernet header, NSX will not update its ARP table as an entry already exists.

Resolution

NSX does not support CARP, or any protocol if the Layer 2 MAC of the GARP packet does not match the ARP header MAC.