bhyve and contention

[Shane Ambler]

On 15/02/2018 05:40, Rodney W. Grimes wrote:
> [ Charset UTF-8 unsupported, converting... ]
>> On 14/02/2018 10:18, Peter Grehan wrote:

>> Be sure not to pass the -S option to bhyve as it wires the guest memory.
>> This was seen recently as sysutils/chyves uses it by default.
> 
> This should be evaluated, if you do not pass -S you run into the
> possible performance impact of swapping guest memory, which does
> infact allow you more over commit, but at a pretty large
> performance penality.

The original question specified having 5 guests with 8G each on a host
with 32G, so overcommitting ram was expected, wiring each guest in this
setup will cause panics not swapping.

> You need swap space if you are going to not pass -S and over commit,
> if you do not have enough swap space for the over commit your system
> runs out of swap and usually ends up killing random processes, and
> random usually means the most important things you are running!

The host has 64G swap setup.


-- 
FreeBSD - the place to B...Software Developing

Shane Ambler