Bug#239208: Sarge beta 3: Error when using installer to resize partition

["Laurens Blankers" <lblankers@xs4all.nl>]

[snip]

>> I continue an change the size value into "512 MB" and select Continue.
>
> You discovered a bug in the partitioner --
> it had to check that 512mb is more than the maximal allowed value.

If the new size is bigger than the maximum possible size (because is
either exceeds the size of the drive or there is an overlap problem with
another partition) you could display a dialog asking the user to either
cancel the operation or resize the partition to the maximum amount
possible.

Alternatively you could allow a special keyword such as MAX when entering
the partition size to allow user the easily specify the maximum amount
possible without needing above dialog.

May be even both.

[snip]

>> Expected behaviour: The installer shrinks the root partition
>> with 512 - 214 MB and increases the size of the swap to 512.
>
> This is not easy to be implemented.  Meanwhile the user is
> expected first to shrink the root partition, second to remove
> the existing swap partition and third to create a new swap
> partition in the free space. The resizing always preserves
> the start of the partition.

[snip]

> We are open for any suggestions.

Oke how about this: Make a distinction between partition already on disk
(actual partitions) and partitions suggested by the installer / created by
the user through the installer before a 'commit' (virtual partitions).

- Allow resizing of a virtual partition.
- When the end of a partition before a virtual partition moves also move
the beginning of the virtual partition. So if you start out with this

#1 3000 MB (virtual)
#2 512 MB (virtual)
Free space at end of disk: 512 MB

And I resize #1 to 2500 the result would be:

#1 2500 MB (virtual)
#2 512 MB (virtual)
Free space at end of disk: 1012 MB

For my specific situation that would mean that in order to increase the
swap partition I have to:

1. Reduce the size of the main partition
2. Increase the size of the swap partition

So without having to remove the swap partion between step 1 and 2. This is
(to me) a more logical procedure.

You could implement this by storing the order of the virtual partitions
relative to the actual partitions instead of start and end position and
only calculate their positions when writing the partition table to disc.

If this causes you a lot of work (and I think it does) I have an easier
solution: The initial problem was that I thought the swap partition
suggested was too small compared to the internal memory (RAM: 192 Swap:
210) other installers suggest a swap partition of about 384 MB (2 x RAM)
which is (for me) a more beter size.

I don't know what algoritme the installer uses to calculate the suggested
swap size, but if you change it to 2 x RAM I would be happy.

Hope this helps.

Sincerly,

Laurens Blankers