To simplify vMotion across CPU generations VMware has introduced Enhanced vMotion Compatibility (EVC). EVC automatically configures server CPUs with Intel FlexMigration or AMD-V Extended Migration technologies to be compatible with older servers. In vSphere 6.5 a now EVC mode has been introduced.
Intel Broadwell Generation
Compared to Intel "Haswell" EVC mode, the 5th Gen Broadwell EVC mode exposes additional CPU features:
- Transactional Synchronization Extensions
- Supervisor Mode Access Prevention
- Multi-Precision Add-Carry Instruction Extensions
- PREFETCHW
- RDSEED
For more information about EVC Modes see Intel CPU EVC Matrix
Am I missing something obvious. I have 2 NUCS one with a 5250u and the other with a 5300u, and yet both cannot join a cluster at broadwell level EVC?
I had a similar problem with Gen7 (Kaby Lake) refusing to work with EVC higher than Sandy Bridge. I used an old flash drive that was previously used with another NUC so I did a fresh install. Now Broadwell EVC still doesn't work, but I can go up to Haswell.
Currently, I have Gen7 (Kaby Lake), Gen6 (Skylake) and Gen5 (Broadwell) CPUs. They should be able to run in Broadwell, but the Gen7 refuses so I have to stick with Haswell.
Not a solution, but I have similar problems with consumer CPUs.
Interesting. I'm having an issue that I can't quite narrow down. I have evc turned off for my two broadwell nucs in a cluster. Some vms can be vmotioned some complain about evc. If I power off the ones that complain vmotion them and then power them on, then they can live migrate.
Twisti, it sounds like you can power then on on the downrev cpu host and then move then they can live anywhere, but if they are powered on on the uprev cpu host, they start using cpu features that some other hosts cannot support.