Re: deprecating /proc/mdstat

[Jes Sorensen <Jes.Sorensen@redhat.com>]

Shaohua Li <shli@kernel.org> writes:
> On Thu, Jan 28, 2016 at 12:41:21PM +0100, Jens-U. Mozdzen wrote:
>> If there's to be a "new mdstat" in /sys, I'd be fine with that. That would
>> help migration for those "old scripts grep'ing /proc/mdstat" you rightfully
>> care about.
>> 
>> I suggest to include a file format version information on line 1
>> "/sys/.../mdstat", that way any client parsing such an interface could
>> verify the file format first, and bail out if it doesn't support the
>> currently presented format.
>
> All the info you can get from /proc/mdstat can be found in /sys/xxx. There
> isn't a central mdstat file in sysfs entry, each sysfs entry only export single
> type info. Version info is uncessary, if we need add new info, we'd just add a
> new sysfs entry.
>
> though the /proc/mdstat will not be deprecated soon, it's highly encouraged app
> switches to /sys. sysfs entry is easy to parse. And as Neil said, /proc/mdstat
> is hard to extend, so new info will likely only appear in sysfs.

I think the strong argument for /proc/mdstat is that it's easy for
visual inspection, but should not be scripted. I certainly use it quite
regularly, but maybe I am just old and lazy :)

Cheers,
Jes