[gpfsug-discuss] Best of spectrum scale

[Stephen Ulmer]

> On Sep 9, 2020, at 10:04 AM, Skylar Thompson <skylar2 at uw.edu> wrote:
> 
> On Wed, Sep 09, 2020 at 12:02:53PM +0100, Jonathan Buzzard wrote:
>> On 08/09/2020 18:37, IBM Spectrum Scale wrote:
>>> I think it is incorrect to assume that a command that continues
>>> after detecting the working directory has been removed is going to
>>> cause damage to the file system.
>> 
>> No I am not assuming it will cause damage. I am making the fairly reasonable
>> assumption that any command which fails has an increased probability of
>> causing damage to the file system over one that completes successfully.
> 
> I think there is another angle here, which is that this command's output
> has the possibility of triggering an "oh ----" (fill in your preferred
> colorful metaphor here) moment, followed up by a panicked Ctrl-C. That
> reaction has the possibility of causing its own problems (i.e. not sure if
> mmafmctl touches CCR, but aborting it midway could leave CCR inconsistent).
> I'm with Jonathan here: the command should fail with an informative
> message, and the admin can correct the problem (just cd somewhere else).
> 

I’m now (genuinely) curious as to what Spectrum Scale commands *actually* depend on the working directory existing and why. They shouldn’t depend on anything but existing well-known directories (logs, SDR, /tmp, et cetera) and any file or directories passed as arguments to the command. This is the Unix way.

It seems like the *right* solution is to armor commands against doing something “bad” if they lose a resource required to complete their task. If $PWD goes away because an admin’s home goes away in the middle of a long restripe, it’s better to complete the work and let them look in the logs. It's not Scale’s problem if something not affecting its work happens.

Maybe I’ve got a blind spot here...

-- 
Stephen

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