Re: [PATCH 0/3] Balance vs device add fixes

Josef Bacik
2021-11-02T13:12:21Z

On Tue, Nov 02, 2021 at 12:52:11PM +0800, Anand Jain wrote:
> On 01/11/2021 19:53, Nikolay Borisov wrote:
> > This series enables adding of a device when balance is paused (i.e an fs is mounted
> > with skip_balance options). This is needed to give users a chance to gracefully
> > handle an ENOSPC situation in the face of running balance. To achieve this introduce
> > a new exclop - BALANCE_PAUSED which is made compatible with device add. More
> > details in each patche.
> >
>
> Have you thought about allowing the device-add during the balance-running,
> not only at the balance-paused? Is it much complicated? If not, then we
> could drop the new exclop state BALANCE_PAUSED altogether.
>

We could be changing the raid settings, adding chunks before the new device is
added and then ending up with chunks that don't have all of their stripes. The
number of bugs that could show up is scary, I think this is the safer choice for
now. Thanks,

Josef