For Vmotion to work between esxhost in a cluster; is it necessary for vmkernel to be able to ping each other ? If they are, does that mean the storage network have to be in one vlan ?
I am thinking of using a non routable IP for connection to the ISCSI san and wonder if I can separate the 2 host on 2 different switches for their ISCSI network ?
I guess my question is, what is the minimum connectivity requirements to get vmotion to work ?
To answer your question, the minimum requirement to get vMotion going would be adding a vmkernel device to the same vswitch as the service console enabling vMotion and away you go....buts thats not to say its a good idea. Best practice would be to create a new vSwitch with a dedicated pNIc create your enabled vmkernel on this. Then using any unroutable address range not already in your org and connect it up using a dedicated pswitch/VLAN. If you have two ESX you can simply back-to-back the two pNics and remove a point of failure.
The same goes for your storage network except you should use a pSwitch and you need both a service console and vmkernel device. Again use any any unroutable address range not already allocated. Best practices says use two pNics for redundacy. To set up ESX according to best practice you need plenty of pNICS!
For VMotion you need a VMKernel port on each ESX server with which they can connect to each other. For iSCSI you need a VMKernel port and a Service console port with access to the iSCSI target. For VMotion to work with iSCSI you need a shared storage - e.g. an iSCSI target which is visible on each ESX server. It's possible to use different VLans for the storage network ports (VMK/SC ports - not the VMotion network ports!) but as they need to see the same target that means that the iSCSI target needs to be connected to a "trunk" port - a port which accepts multiple vlans (because each ESX server needs to see the exact same target...)
Requirements for VMotion: VMKernel port, shared storage, same network names, no local storage connection (e.g. CD-Rom isos, ...), ... on each ESX server
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