Re: migrating raid-1 to different drive geometry ?

On Monday January 24, rfu@kaneda.iguw.tuwien.ac.at wrote:

how can the existing raid setup be moved to the new disks 
without data loss ?

I guess it must be something like this:

1) physically remove first old drive
2) physically add first new drive
3) re-create partitions on new drive
4) run raidhotadd for each partition
5) wait until all partitions synced
6) repeat with second drive

Sounds good.

the big question is: since the drive geometry will definitely different
between old 60GB and new 80GB drive(s), how do the new partitions 
have to be created on the new drive ?
- do they have to have exactly the same amount of blocks ?

No.

- may they be bigger ?

Yes (they cannot be smaller).

However making the partitions bigger will not make the arrays bigger.

If you are using a recent 2.6 kernel and mdadm 1.8.0, you can grow the
array with
   mdadm --grow /dev/mdX --size=max

You will then need to convince the filesystem in the array to make use
of the extra space.  Many filesystems do support such growth.  Some
even support on-line growth.

NeilBrown