vMotion Enhancements on ESX 4.1

Significantly decreased the overall migration time (time will vary depending on workload) 

 Increased number of concurrent vMotions:

   

  ESX host: 4 on a 1 Gbps network and 8 on a 10 Gbps network 

  Datastore: 128 (both VMFS and NFS)

Maintenance mode evacuation time is greatly decreased due to above improvements

        Re-write of the previous vMotion code

•   Sends memory pages bundled together instead of one after the other
•   Less network/ TCP/IP overhead

• Destination pre-allocates memory pages
• Multiple senders/ receivers

  Not only a single world responsible for each vMotion thus limit based on host CPU

•          Sends list of changed pages instead of bitmaps

        Performance improvement

•          Throughput improved significantly for single vMotion

  ESX 3.5 – ~1.0Gbps

  ESX 4.0 – ~2.6Gbps

  ESX 4.1 – max 8 Gbps

•          Elapsed reduced by 50%+ on 10GigE tests. 

        Mix of different bandwidth pNICs not supported