Cloning 1 hard disk in a software RAID

[Colin Law]

2009/7/28 Liam Proven <lproven at gmail.com>:
> 2009/7/28 Alvin Chang <alvin.chang at gmail.com>:
>> On Tue, Jul 28, 2009 at 16:20, Liam Proven <lproven at gmail.com> wrote:
>>>
>>> I have a degraded & rather unstable software RAID on my server. 1 disk
>>> does not register at all any more & the md subsystem won't mount it as
>>> being "stale". Another sometimes mounts but won't stay up for long.
>>
>> What does cat /proc/mdstat say? Which RAID level is it?
>>
>>>
>>> <snip>
>>> dd if=/dev/sdd of=/dev/sde
>>>
>>> to copy the whole of the unstable drive onto a new one.
>>>
>>> Should this work, or is it a disastrously bad idea or something?
>>
>> Well, that really depends... if the source drive is broken, you might need
>> to use something other than dd to clone the disk so that it ignores bad
>> sectors, e.g. Gohst 4 Linux...
>
> I don't think I have any bad blocks, it just won't always spin up.
>
>> In fact, if you are using RAID5 or above... simply re-initialize the array
>> with a working blank drive should do the trick.
>
> Tried that; nothing seems to happen & this is the only copy of the
> data that I have so I am wary of experimenting too much...

I am sure will already have done this but backup the _really_
important stuff onto CD or another machine or something before doing
anything else

Colin