Re: [Qemu-devel] Re: [PATCH] Add cache=volatile parameter to -drive

[Anthony Liguori <anthony@codemonkey.ws>]

On 05/17/2010 11:23 AM, Paul Brook wrote:
>>> I don't see a difference between the results. Apparently the barrier
>>> option doesn't change a thing.
>>>        
>> Ok.  I don't like it, but I can see how it's compelling.  I'd like to
>> see the documentation improved though.  I also think a warning printed
>> on stdio about the safety of the option would be appropriate.
>>      
> I disagree with this last bit.
>
> Errors should be issued if the user did something wrong.
> Warnings should be issued if qemu did (or will soon do) something other than
> what the user requested, or otherwise made questionable decisions on the
> user's behalf.
>
> In this case we're doing exactly what the user requested. The only plausible
> failure case is where a user is blindly trying options that they clearly don't
> understand or read the documentation for. I have zero sympathy for complaints
> like "Someone on the Internet told me to use --breakme, and broke thinks".
>    

I see it as the equivalent to the Taint bit in Linux.  I want to make it 
clear to users up front that if you use this option, and you have data 
loss issues, don't complain.

Just putting something in qemu-doc.texi is not enough IMHO.  Few people 
actually read it.

Regards,

Anthony Liguori

> Paul
>
>