Hi Ken,

vMotion has not changed to allow it to be routable.  I hope one day it will be... But I think the performance would be a major issue and the VMs would start to complain.

Best regards,

Edward Haletky

The recommended default gateway for VMotion in ESX2 was the same as the VMotion IP address.

In ESX3 now, we are to use the actual default gateway (if applicable) for the VMotion subnet.  Since we're configuring values for a VMKernel switch, I would bet VMotion could be routed through the gateway, much the way other VMKernel traffic can be routed such as ISCSI or NFS.

This would be pretty easy to set up and test if anyone wants to put the hour or so into it.  My lab is a routed network with multiple subnets so if I can get away from the Citrix project I'm buried in, I'll give it a whirl and let you know what I find out Ken.

Hello,

Since vMotion uses its own protocol, the router would have to understand that protocol. I have not heard any do. When a vMotion occurs the iSCSI/NAS network is not really being accessed.... Still I agree, it seems like it could work, but would it still be fast enough? Please post the results of your test. I do not have the network capacity here to run my own yet.

Best regards,

Edward

Ok.. maybe tonight.  Home lab is routable also.

VMotion across a router to a different subnet completed successfully.  Although, it ran slowly at first because I forgot that I was packet shaping on the router to simulate a T1 WAN link.  So basically when I started, I was VMotioning over a 1.544Mbps T1

Jas

Yep I've managed and tested this before, I didn't notice any speed differences however. Hmmmm

One of the issues I can see is that you would be adding more complexity to the process which could make troubleshooting vMotion problems much more difficult. This is certainly not something to be put in without a fair bit of planning.

Hello,

That is a very nice change! Can you give us the specifics? What subnet to what subnet? Where were the netmasks involved? When you setup the default gateway for each side, how were they setup?

How far apart where the subnets?

Even so, I am not sure I would do this on anything that was not a dedicated link. I can just see people trying to vMotion over a non-dedicated link. Remember vMotion is unencrypted so the memory footprint is available to a man in the middle attack.

Best regards,

Edward

Yep I've managed and tested this before, I didn't

notice any speed differences however. Hmmmm

Hi Vliegenmepper   

I had the performance issue because my router bandwidth was capped at 1.544Mbps incoming and outgoing in order to simulate a WAN link in the lab.

Everything else being equal, I would expect there would be some decrease in speed due to the simple fact that an extra hop and piece of equipment has been added in between the path of the VMotion.  When you boil it down, the router needs to process the flurry of frames that pass through it which will add some degree of overhead, whether measurable or not.

Hi Jason,

Clear to me now, I agree you'll loose some performance all depending on your network setup.

I just tested with an extra router in the core switch. VMotioned from 192.168.1.0 to 10.0.0.0 subnet. It was more to see if it worked or not.

Brings up some interesting possibilities.  I wonder how creative people might get