Cloning 1 hard disk in a software RAID

[Liam Proven]

2009/7/28 Colin Law <clanlaw at googlemail.com>:
> 2009/7/28 Liam Proven <lproven at gmail.com>:
>> 2009/7/28 Colin Law <clanlaw at googlemail.com>:
>>> 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
>>
>> I can't, the array won't stay up long enough... Thus the last-ditch
>> efforts to try to get some stuff off the blasted thing.
>>
>
> I don't know much about RAID so this may be a silly suggestion.  Could
> you take the sometimes working disk out and plug it in to a different
> PC (or the same one) as a single disk rather than part of the RAID
> set?  Or can it not work on its own?  Not that this will help if the
> disk won't keep going.

They are 4 ordinary 40GB EIDE drives. I've already moved the whole
array to a new server, a Dell PowerEdge 600SC. I was planning to
attach the iffy one(s) in isolation to clone them, yes.


-- 
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