[plug] harddrive becomes read-only

[Daniel Pittman]

Gavin Chester <gavin.chester at gmail.com> writes:
> On Sun, 2008-09-07 at 23:23 +0800, Keith Bawden wrote:
>> On Sun, Sep 7, 2008 at 22:43, Gavin Chester <gavin.chester at gmail.com> wrote:
> [...]
>> Grown defects might be harmless, however if the number is high (I
>> would say 36 is might be getting there) this could indicate eminent
>> disk failure. IMHO, If the number is growing quickly then it is pretty
>> much time to swap it out. These "defects" are parts of the disk marked
>> as bad and as such the OS should ignore the defective areas. The
>> address of these areas are detailed in the "defect list".
> [...]
>
> Okay, thanks for your advice. I have other discs to replace it with.
> Trouble is, I used LVM for the first in my life and did it half-baked
> (ie., not understanding all it's ins-n-outs) so am unclear how I might
> swap out one drive from a 2-drive logical volume :-/

The high level process is:

1. Add the extra disk to the system, and get into Linux.
2. Use pvcreate to make it available as a physical disk.
3. Use pvmove to transfer the physical extents from the old disk to the
   new one.
4. Use pvremove to remove the old physical disk.
5. Pull the old hardware and throw it away, or whatever.

Note that pvmove has some requirements for free logical space, and so
forth, so a target disk exactly the same size as the source with no
logical space free might be an issue.

Anyway, read up about those utilities and the LVM howto, and you should
be well placed to ask sensible questions.

Regards,
        Daniel