Hi Wol,
> I wouldn't think it necessary to scrap the array, but if you've backed
> it up and are happier doing so ...
Not particularly. I have taken backups and I am reshaping it to 5 raid
devices and if it works, I'll keep it.
> As for the "invalid backup" problem, you should never have given it a
> backup in the first place, and (while I don't know the code) I very much
> expect it ignored the option completely.
I don't know, Wol. I added the option because the wiki recommended it.
All I know is that when I tried to resume the reshape without the
option or without the --invalid-backup option, mdadm complained it
could not restore the critical section and refused to assemble the
array.
> Once an array goes through reshapes, it can be a lot harder to work
> out the layout if you have to rescue the array by recreating it.
I am no longer going to rely on the array alone to keep my data safe.
Should this array ever fail again, there will be backups to recover
from.
Thanks,
Johan
On Sat, May 6, 2023 at 11:59 PM Wol <antlists@xxxxxxxxxxxxxxx> wrote:
>
> On 06/05/2023 14:07, Jove wrote:
> > Hi Kuai,
> >
> > Just to confirm, the array seems fine after the reshape. Copying files now.
> >
> > Would it be best if I scrap this array and create a new one or is this
> > array safe to use in the long term? It had to use the --invalid-backup
> > flag to get it to reshape, so there might be corruption before that
> > resume point?
> >
> > I have to do a reshape anyway, to 5 raid devices.
> >
> I wouldn't think it necessary to scrap the array, but if you've backed
> it up and are happier doing so ...
>
> AIUI it was an external program squeezing in where it shouldn't that
> (quite literally) threw a spanner in the works and jammed things up. The
> array itself should be perfectly okay.
>
> As for the "invalid backup" problem, you should never have given it a
> backup in the first place, and (while I don't know the code) I very much
> expect it ignored the option completely. You have superblock 1.2, which
> has a chunk of space "reserved for internal use", one of which is to
> provide this backup.
>
> The only real good reason I can think of for scrapping and recreating
> the array is that it will give you a clean array, with ALL THE CURRENT
> DEFAULTS. This is important if anything goes wrong in future, if you
> have an array with a known creation date, that has not been "messed
> about" with since, it's easier to recover if you're really stupid and
> damage it and lose your records of the layout. Once an array goes
> through reshapes, it can be a lot harder to work out the layout if you
> have to rescue the array by recreating it.
>
> Cheers,
> Wol
