Re: mdadm: Patch to restrict --size when shrinking unless forced

[Jes Sorensen <jes.sorensen@gmail.com>]

On 10/10/2017 04:54 PM, Wols Lists wrote:
> On 10/10/17 21:09, Jes Sorensen wrote:
>>> Both operations would share the current code, just apply a different
>>> sanity check before proceeding.
>>
>> "grow" in mdadmlish translates to reshape/resize in English. Starting to
>> introduce new keywords for this really makes no sense and just cause
>> confusion, so I am not going to support that.
> 
> But saying "grow" when the result is a shrink also causes confusion.
> Would you accept changing "grow" to "resize"?

Changing an existing keyword that people have been using for years isn't 
going to make anything better. There are scripts in place, people have 
systems with old and new installed.

> But personally I think adding a new keyword is sensible. Firstly, in
> normal use no-one is ever going to want to shrink an array, so this is
> rarely going to be used.
> 
> And secondly, if you use "grow" to grow an array, it's a "safe"
> operation (unless something goes wrong). If you use "grow" to *shrink*
> an array, as Eli found out, it's very dangerous.
> 
> I think abusing the English language is far more dangerous than adding a
> new keyword. No disrespect to them, but you forget your average sysadmin
> is, well, average. Handing them a loaded foot-gun with no safety-catch
> is *not* a good idea. (And even a good sysadmin will spend little time
> with mdadm. Even if they know this now, there's a good chance they'll
> forget before they need it again, and it becomes a land-mine waiting to
> go off ...)

In this case a good sysadmin will read the man page and follow the 
instructions.

The English abuse isn't an argument I really buy. There are millions of 
cases out there for that.

Jes