Network traffic over backplane traffic

[AdamJamal]

I wonder if anyone can help here.... i've got 4 hosts in a cluster, connected to a san.

I've noticed when copying  data between vm's (even on the same subnet and host) the data leaves the host, hits the gateway and comes back.

How do i stop it leaving the hosts/san to improve data transfer speeds between vm's?

Many thanks.

P.S. ESXi 5 and XIV storage.

[schepp]

Hi welcome to the communities,

to prevent the data from leaving the host, keep the two VMs that copy files on the same host on the same portgroup. This way the traffic will only pass the vSwitch and won't go through your physical switch.

Take a look at: http://itknowledgeexchange.techtarget.com/virtualization-pro/how-traffic-routes-between-vms-on-esx-hosts/

Regards

[AdamJamal]

Can  i ask for a small expansion on that, so i have 3 subnets (eg 10.200.8.0, 10.200.16.0, 10 200.32.0 all with 255.255.255.0 masks).  I have 300 vms spread out over those vlans, what is the best approach to keep the data internal, ie is there a limit on the number of vms assigned to a port?  Whats the best want to design this solution?

Many thanks

[a_p_]

You can configure up to 4,088 ports per host with 1,016 being active, so the limit is not an issue in your case. However, you may need to reconfigure the number of ports in the vSwitch settings, which requires a host reboot in order to take effect. (for configuration maximums see http://www.vmware.com/pdf/vsphere5/r50/vsphere-50-configuration-maximums.pdf)

With 3 port groups (one for each VLAN) on the vSwitch, the traffic within each of subnet will remain intenally, whereas traffic between subnets requires routing, i.e. leaves the host.

André

[AdamJamal]

Many thanks to you both, this has helped a lot, i will implement the suggestion and will come back if i hit any issues....

[AdamJamal]

Ok, a little more information here.... so i have a port group on subnet 1 vlan 2, i have a second port group on subnet 2 vlan 4 and i have a third port group on subnet 3 vlan 6; all on a single vswitch  My hosts are clustered.

-  If i have 2 vm's on subnet 1 vlan 2 should the data route internally? Does it make a difference if they are on different hosts?

-  If i have 2 vm's and one is on subnet 1 vlan 2 and the second is on subnet 3 vlan 6, should the data route internally?

- Do i require a seperate vswitch for each vlan/subnet?

What im observing at the moment is data being sent to the gateway for the 10.200.8.0 network even though the vms are on the same subnet, my understanding is this should route internally?

[a_p_]

If i have 2 vm's on subnet 1 vlan 2 should the data route  internally? Does it make a difference if they are on different hosts?

For VM's on the subnet and the same host traffic should only go through the vSwitch, for traffic across hosts, at least the external switch is involved.

If i have 2 vm's and one is on subnet 1 vlan 2 and the second is on subnet 3 vlan 6, should the data route internally?

No, since traffic between subnets has to be routed, the traffic has to go through the gateway/router.

Do i require a seperate vswitch for each vlan/subnet?

Assuming the uplink ports on the physical side a re configured as 802.1Q ports, you can have all port groups on a single vSwitch.

If this is not the case in your environment, please describe your setup (virtual and physical).

André