[SOLVED] processor type KVM64 or specific?

[godfather007]

Hi,

when creating a VM, it is possible to define KVM64 (default) or a specific CPU instruction.

When all hosts are equal, is it best to select the specific type of CPU to use that specific CPU's features?

Regards,
Martijn

 

[sidereus]

When all hosts are equal, is it best to select the specific type of CPU to use that specific CPU's features?

There is the CPU type "host" at the end of the list for a such case.

 

[godfather007]

Thx, that's usefull..

Just experimented with a CPU-ID tool and indeed, the more modern flags are exposed when using the correct CPU, whereas KVM64 has an old instruction set exposed.

 

[ph0x]

Kvm64 contains a small subset of instruction sets so that interoperability is guaranteed.
CPU types will only make problems when you try to live migrate to a system where the CPU cannot provide instruction sets that you defined.
If all your nodes are the same you can easily choose "host" since this would give you the lowest overhead in processor usage.
And even if they're not the same you only have to make sure to use the least modern CPU type and will still face no problems with live migration.

 

[binaryanomaly]

Kvm64 contains a small subset of instruction sets so that interoperability is guaranteed.
CPU types will only make problems when you try to live migrate to a system where the CPU cannot provide instruction sets that you defined.
If all your nodes are the same you can easily choose "host" since this would give you the lowest overhead in processor usage.
And even if they're not the same you only have to make sure to use the least modern CPU type and will still face no problems with live migration.

Thanks, very useful information. I didn't know that and kinda assumed that kvm64 would make sense. It does not at all for my context.