Re: [gentoo-user] How to change from one harddrive to software raid

[Florian Philipp]

Am 30.03.2011 07:28, schrieb Florian Philipp:
> Am 30.03.2011 05:02, schrieb Einux:
>> Hi,
>>
>> I bought a new 1T harddrive which is exactly the same as my previous
>> harddrive. So I'm planning to make a Raid-1 layout(for security
>> reasons). But here's the problem: I've already setup LVM2 on the
>> existing harddrive and I don't want to destroy the existing LVM volume
>> groups. I tried to google it, but I'm not sure which is the right keyword.
>> Could you guys help me out?
>>
>> Thanks in advance:)
>>
>> --
>> Best Regards,
>> Einux
>>
>
> 1. Create a degenerated RAID1 with your new disk
> mdadm --create /dev/md0 --level=1 --raid-devices=2 missing /dev/sdb
>
> 2. Partition the raid device
>
> 3. Add one of the partitions to your LVM volume group.
> pvcreate /dev/sdb2
> vgextend volume_group /dev/sdb2
>
> 4. Move everything from the old physical volumes to the new pv.
> pvmove /dev/sda3 /dev/sdb2
>
> 5. Remove the old and now empty physical volume
> vgreduce volume_group /dev/sda3
>
> 6. Move everything else which is not on LVM to your new raid. Guess you
> need to go to single user mode to do this safely.
>
> 7. Grow your raid to also contain the old disk.
> mdadm /dev/md0 -a /dev/sda
>
> No, I have not tested this and you should double-check everything. No
> guarantees, etc.
>
> One warning, though: pvmove is known to create problems from time to
> time. Leaking memory, bogging systems with infinite system load and so
> on. If it gives you trouble, you can abort it with `pvmove --abort` and
> try it again later by calling `pvmove volume_group` (without physical
> device specified) to resume it. It SHOULD survive system crashes.
> Trying another kernel version sometimes helps when pvmove gives you trouble.
>
> Hope this helps,
> Florian Philipp
>

Argh,
of course a partition on md0 is not called sdb2. Just if that got you
confused ;)