[sheepdog] [PATCH 4/4] dog: make repairing vdi optional

[MORITA Kazutaka]

At Thu, 22 Aug 2013 22:45:43 +0800,
Liu Yuan wrote:
> 
> Actually I think users should not know any options at all. Anyone tries to run
> vdi check, is just to check the health of the targeted vdi.

I agree to this, but...

> 
> >  - It's difficult to maintain bash_completion_dog and dog.8 if we
> >    allow the option list.
> > 
> > How about adding only one option "-o, --online", which filters unsafe
> > check/repair when the vdi is in use?
> > 
> > E.g.
> > 
> > $ vdi check                   # This tries full check.
> > $ vdi check --online          # This filters consistency check since it
> >                               # doesn't work if the vdi is in use
> > 
> > $ vdi check --repair          # This tries full check and repair
> > $ vdi check --repair --online # This does only existence check since
> >                               # the other tests are not safe against online vdi.
> > 
> 
> From the view of ordinary user, I think concept like existence, inode, consistency
> won't make too much difference to them. If I were the user, I'd expect
> 
> $ vdi check # this will check the health and report the problem if any
> $ vdi check -r # if problems reported, users can decide to repair, whatever problem is
> 
> That is all. For advanced users,
> $ vdi check -o {option list}
> or
> $ vdi check -opt1 -opt2 -opt2 # for easier bash_completion_dog generation.

please take into account the user who are not familiar with the
detailed option but want to check without stopping VMs.  Online health
checking is definitely necessary and I know actual users who need it
inside and outside my company.  SAN storages also usually support
scheduled health checking (without stopping storage service, of
course).

IMHO, unsafe options should be filtered out by default and enabled
only when user explicitly enable it.  In the production service, it is
difficult to stop all the VMs only for periodic health check and
online checking is more common.  Even if it is not acceptable, please
consider the way to do online health check easily.

Thanks,

Kazutaka