Re: [gentoo-user] Re: Resizing a FAT partition?

[Mick]

On Thursday 30 Jul 2015 20:52:24 Francisco Ares wrote:
> 2015-07-30 16:26 GMT-03:00 Grant Edwards <grant.b.edwards@×××××.com>:
> > On 2015-07-30, Neil Bothwick <neil@××××××××××.uk> wrote:
> > > On Thu, 30 Jul 2015 20:32:05 +0200, Meino.Cramer@×××.de wrote:
> > >> Firstly I want to shrink the first partition and secondly it is a
> > >> plain FAT32 partition not ext-something. I did not find a
> > >> "resizefat32" or similiar.
> > >
> > > You need fatresize, which doesn't appear to be in portage. The approach
> > > when reducing a partition's size is to first reduce the size of the
> > > filesystem, to slightly less than the final partition size for safety.
> > > Then delete and recreate the partition, with the same starting point.
> > > Finally resize the filesystem to fill the new partition.
> > >
> > >> What tools do I need?
> > >
> > > The easiest way is probably to use GParted, which does all the hard
> > > work for you, just tell it the new size of the partition. It will also
> > > create the second partition for you, as a bonus.
> >
> > I've read good things about Parted Magic:
> >   https://partedmagic.com/
> >
> > AFAICT, it's a friendly front-end to parted (as is GParted), but also
> > includes some extra abilities like cloning partitions and disks for
> > backup purposes.
> >
> > >> (beside the way to backup the SDcard, reinitialize it, put 2
> > >> partitions on it and copy back the stuff.)
> > >
> > > Given that you should backup any important data before resizing any
> > > filesystem, this may be the easiest method.
> >
> > I've had resize operations go pear-shaped on me.  I haven't seen it
> > often, but I wouldn't attempt a resize without a backup copy of the
> > partition involved.
> >
> > --
> > Grant Edwards               grant.b.edwards        Yow! Did YOU find a
> >
> >                                   at               DIGITAL WATCH in YOUR
> >
> > box
> >
> >                               gmail.com            of VELVEETA?
>
> Flash memory devices are tricky when you try do defrag, as there is extra
> logic inside them to do the opposite: spread as much data as possible, as
> to equalize the number of write operations - the main limit for flash
> memory - for all sectors.
>
> Most defrag tools do this by reading files to RAM, reordering them, erasing
> the originals from the media, then writing them again, using no direct
> sector access, leaving that to the operating system. And it works on
> magnetic media, as it creates empty spaces suitable for continuous files.
>
> So that extra logic may fool you, making you believe it worked, when it
> didn't.
>
> Considering this, as already said, I would copy everything to another
> media, set up a new partition layout, format the new partitions as desired,
> then get all data back to the new layout.
>
> Just my 2 cents, of course.
>
> Good luck
> Francisco

Good catch - I didn't notice it was an SDcard.  Yes, defrag does not apply.

-- 
Regards,
Mick