Re: [gentoo-user] Process to resize ext3 file system at the command line?

[Mark Knecht]

On Thu, Nov 17, 2011 at 10:43 AM, Michael Mol <mikemol@×××××.com> wrote:
> On Thu, Nov 17, 2011 at 1:29 PM, Mark Knecht <markknecht@×××××.com> wrote:
<SNIP>
>> At this point I was told:
>>
>> "Now, resize your filesystem to use the additional space."
>>
>> So, if at this point the end-block of sda6 isn't 976768064 but, let's
>> say, 700000000 because mdadm set it to something new, then using your
>> suggestion I guess I'd set it back to 976768064? I'm not comfortable
>> however that if I do that that whatever is out there beyond 700000000
>> is really formatted as ext3 and 'empty' as I don't know what the mdadm
>> conversion has done to it.
>
> Your resize would be applied not to /dev/sd?, but to /dev/md?. You
> don't need to worry about what that means on /dev/sd*; the filesystem
> you want to poke is on /dev/md*.
>
> file -s /dev/sd* /dev/md*
>
> --
> :wq

Yes, resize would be done to /dev/md?. I agree. However I don't
believe that I'd use Neil's suggestion of fdisk block numbers on
/dev/md, right? That doesn't make sense to me and I don't beleieve
Neil was suggesting anything like that.

I'm thinking that possibly the mdadm way to change the _size_ of a
RAID is to once again use the grow option:

<quote>
       -G, --grow
              Change the size or shape of an active array.
<quote>

I've not yet found any instructions that I trust to do it though, and
being that the instructions above came from, among others, Neil Brown
who manages mdadm I'm hesitant to go in my own direction. I'm just
looking before I leap.

And fortunately, if I decided to just blow away all three disks and
start from scratch I have very little at risk that way, and very
little risk as I will do backups of the RAID-1 onto an external USB
drive before I start this process anyway.

- Mark