Dramatically improve replication performance and avoid RPOs.

Hi All,

Writing this blog to assist with replication setup.

Traffic isolation is key. Here is what this looks like.

Ref: https://docs.vmware.com/en/vSphere-Replication/8.4/com.vmware.vsphere.replication-admin.doc/GUID-16677363-4265-4815-9C1C-DAAA3AE500CD.html?hWord=N4IghgNiBcIC4CcwDNkEsDGACNBnA9hGHGvgHYgC+QA

Adding 2 NICs to the 8.4 appliance requires some additional work.

• NEW You cannot configure the network card settings in the VRMS Appliance Management InterfaceYou cannot see the second and/or third network card in the Networking page of the VRMS Appliance Management Interface.Workaround:1. Power off the VM.
  2. Add a new Network card.
  3. Power on the VM.
  4. In the virtual appliance console, run the ip addr command to see the network details and the name of the newly added network card. The network card should have a state DOWN and a name eth1, for example.
  5. In the virtual appliance console, run the following command:
  sudo /opt/vmware/bin/create_nic_config.sh <new network card name>
  For example:
  sudo /opt/vmware/bin/create_nic_config.sh eth1
  Note that new NIC will be configured with DHCP IPv4 address by default.
  6. Use the VRMS Appliance Management Interface to configure the network settings for the newly added network card, if required.

When adding IP addresses use the gateway for the management NIC. VR does not support multiple gateways.

Then we can add a route with the gateway for that network in the NIC.

# vim /etc/systemd/network/10-eth1.network

vim /etc/systemd/network/10-eth2.network

The NIC of the VR appliances will look like this.

The VMkernels of the ESXi host will look like this.

Adding static routes ESXi.

https://kb.vmware.com/s/article/2001426

1. To add a static route, run the command:
   
   esxcli network ip route ipv4/ipv6 add –gateway IPv4_address_of_router –network IPv4_address
   
   For example, to add a route to 192.168.100.0 network with a /24 bit subnet mask (255.255.255.0) through a router with an IP address of 192.168.0.1, run this command:
   
   esxcli network ip route ipv4 add –gateway 192.168.0.1 –network 192.168.100.0/24
   
2. To list the route, run the command:
   
   esxcli network ip route ipv4 list
3. To remove a static route, run the command:
   
   esxcli network ip route ipv4 remove -n network_ip/mask -g gateway_ip

Conclusions.

1.To get the extra benefit from traffic isolation we need to seperate the NFC traffic from the vSphere replication traffic. Often we overlook this and move all the replication and NFC traffic to the same VMkernel creating a bottle neck.

Adding a second nic is outlined in the release notes with the script.

2.MTU 9000 can be used on the vmkernels if your switch supports it.

3. Adding the routes is a critical step for the replication traffic between sites, ensure to only use gateway of the management network.

4. Adding vmkernels to ESXi host requires planning of IP range and IP addresses. Recommend to use a google doc to keep track and share with your work colleagues. We don’t want Kate Jane or Joe setting up the new office printer or virtual gaming hub with your IP ranges:).