[Libguestfs] [PATCH] New API: mdadm-stop for stopping MD devices.

[Wanlong Gao]

On 11/24/2011 01:11 AM, Matthew Booth wrote:

> On 23/11/11 16:22, Richard W.M. Jones wrote:
>> On Wed, Nov 23, 2011 at 03:02:19PM +0000, Matthew Booth wrote:
>>> On 23/11/11 14:43, Wanlong Gao wrote:
>>>> This API is used to stop a md device.
>>>> When we want to move a device to another md array, we should
>>>> stop the md device which contained this device first.
>>>
>>> I'm not convinced we should extend the md api in libguestfs to
>>> active manipulation. I wasn't convinced that mdadm-create was
>>> worthwhile either, but it made a test case ever so slightly tidier.
>>> To me, MD devices are the domain of physical machines. We need to be
>>> able to *read* them (for P2V apart from anything else), but I think
>>> manipulation is opening an unnecessary can of worms.
>>
>> But is there any penalty to carrying this?
> 
> I can think of 2:
> 
> 1. Maintenance: I know you think this is free, but some day mdadm --stop 
> might change behaviour, and then the api will break.


I think it'll not, but if it does, we can change the internal to fix the behavior.

> 
> 2. A false sense of expectation: Having an incomplete md api can only 
> lead to frustration. Implementing a complete md api would require a 
> large amount of effort for something which we don't have a convincing 
> use case for (i.e. nobody's ever going to use it anyway).


But IMO, we at least support the create and stop API, along with reading the
MD together?

> 
> Matt