Re: [Qemu-devel] [PATCH] hw/vexpress: set default block type to SD

[Paolo Bonzini <pbonzini@redhat.com>]

Il 15/03/2013 16:35, Peter Maydell ha scritto:
> On 5 March 2013 00:44, Aurelien Jarno <aurelien@aurel32.net> wrote:
>> On Tue, Mar 05, 2013 at 08:22:57AM +0800, Peter Maydell wrote:
>>> What effect does this actually have on the user experience?
>>
>> The effect is that the user don't has to specify the interface type.
>> Basically:
>>
>>   -drive file=/path/to/file,if=sd
>> can be replaced by
>>   -drive file=/path/to/file
>>
>> It means the user doesn't have to know the details of the machine to
>> know how to attach a disk. Note that the user here can also be a script,
>> which then becomes a bit simpler.
> 
> I'm not convinced this is a good thing -- I think you should have
> to know that you're attaching an SD card and not a hard disk,
> because the performance is much worse. In particular if you
> don't specify 'cache=writeback' your performance will be
> dreadful, so you need to do something different from hard
> disks anyhow.

cache=writeback has been the default for a few releases.

Paolo