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