Re: Raid 5 Array

[Simon Mcnair <simonmcnair@gmail.com>]

Marcus,
Please reply all and keep the list in cc

Please also post the commands used to create the arrays and the fdisk output ?

The other thing of note, I think is that when you have multiple arrays
I believe the recommendation is to use mdadm.conf as a 'hint' file so
that this doesn't happen ?

On 2 Apr 2011, at 21:20, Marcus <nexuslite@gmail.com> wrote:

> My raid is opposite of that I am putting raid0's into a raid5 rather
> than raid5's into a raid0 but from the looks of what you have sent me
> I am not suppose to add a partition to the raid that is going into the
> main raid?
>
> I guess I will play with it some more and hopefully I don't lose
> everything. I just don't like waiting 4 hours for it to rebuild the
> drive to find out it doesn't work.
>
> Thanks for the help.
>
> On Sat, Apr 2, 2011 at 1:09 PM, Simon McNair <simonmcnair@gmail.com> wrote:
>> cc'd the list back in as I'm not an md guru.
>>
>> I did a search for mdadm raid 50 and this looked the most appropriate.
>>
>> http://books.google.co.uk/books?id=DkonSDG8jUMC&pg=PT116&lpg=PT116&dq=mdadm+raid+50&source=bl&ots=Ekw6NCiXqR&sig=edBYg9Gtd5RXyuUU0PeSpHvS7pM&hl=en&ei=9YGXTYyeBcGFhQe90ojpCA&sa=X&oi=book_result&ct=result&resnum=5&ved=0CEIQ6AEwBA#v=onepage&q=mdadm%20raid%2050&f=false
>>
>> Simon
>>
>> On 02/04/2011 20:38, Marcus wrote:
>>>
>>> Yes I used --zero-superblock this time. I think that was my problem
>>> last time it kept detecting the drives at random and creating odd
>>> arrays. This time I am not sure what my problem is. I got two drives
>>> back up so I have my data back but I tried getting the two raid0
>>> drives to become part of the raid5 twice so far and each time fdisk -l
>>> shows the wrong sizes for the raids when they are combine the first
>>> time it showed the small raid as 1TB which is the size of the big raid
>>> the second time it showed the big raid as 750GB which is the size of
>>> the small array. Some how the joining of the two raids is corrupting
>>> the headers and reporting wrong information.
>>>
>>> Is there a proper procedure for creating a raid0 to put into a raid5?
>>> last time I created my raid0 and added a partition to the raids and it
>>> automatically dropped the partition and just showed md0 and md1 in the
>>> array instead of md0p1 and md1p1 which was the partition i added to
>>> the array. I have tried adding the partition into the array and I also
>>> tried adding just array into the array. neither method seems to be
>>> working this time.
>>>
>>> On Sat, Apr 2, 2011 at 12:01 PM, Simon McNair<simonmcnair@gmail.com>
>>> wrote:
>>>>
>>>> Hi,
>>>> I'm sure you've tried this, but do you use --zero-superblock before
>>>> moving
>>>> disks over ?
>>>>
>>>> Simon
>>>>
>>>> On 02/04/2011 19:51, Marcus wrote:
>>>>>
>>>>> I have a raid array this is the second time an upgrade seems to have
>>>>> corrupted the array.
>>>>>
>>>>> I get the following message from dmesg when trying to mount the array
>>>>> [  372.822199] RAID5 conf printout:
>>>>> [  372.822202]  --- rd:3 wd:3
>>>>> [  372.822208]  disk 0, o:1, dev:md0
>>>>> [  372.822212]  disk 1, o:1, dev:sdb1
>>>>> [  372.822216]  disk 2, o:1, dev:sdc1
>>>>> [  372.822305] md2: detected capacity change from 0 to 1000210300928
>>>>> [  372.823206]  md2: p1
>>>>> [  410.783871] EXT4-fs (md2): Couldn't mount because of unsupported
>>>>> optional features (3d1fc20)
>>>>> [  412.401534] EXT4-fs (md2): Couldn't mount because of unsupported
>>>>> optional features (3d1fc20)
>>>>>
>>>>> I originally had a raid0 md0 with two 160GB drives, a raid0 md1 with
>>>>> 250GB and md0, a raid 5 with a 1.0TB, 500GB, and md1
>>>>>
>>>>> I swapped out md1 with a new 1TB drive which worked. then i dropped
>>>>> the 500GB and combined it with the 250GB drive to make a 750GB drive
>>>>>
>>>>> The error seems to come when you reintroduce drives that were
>>>>> previously in a raid array into a new raid array. This is the second
>>>>> time I have ended up with the same problem.
>>>>>
>>>>> Any suggestions on how to recover from this or is my only option to
>>>>> reformat everything and start again?
>>>>> --
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>>