Re: Raid5 reshape

[Tim T <irule@irule.net>]

You have to grow the ext3 fs separately. ext2resize /dev/mdX. Keep in 
mind this can only be done off-line.

-Tim

Nigel J. Terry wrote:
> Neil Brown wrote:
>> On Thursday June 15, irule@irule.net wrote:
>>  
>>> Hello all,
>>>
>>> I'm sorry if this is a silly question, but I've been digging around for
>>> a few days now and have not found a clear answer, so I'm tossing it out
>>> to those who know it best.
>>>
>>> I see that as of a few rc's ago, 2.6.17 has had the capability of 
>>> adding
>>> additional drives to an active raid 5 array (w/ the proper ver of 
>>> mdadm,
>>> of course). I cannot, however, for the life of me find out exactly how
>>> one goes about doing it! I would love if someone could give a
>>> step-by-step on what needs to be changed in, say, mdadm.conf (if
>>> anything), and what args you need to throw at mdadm to start the 
>>> reshape
>>> process.
>>>
>>> As a point of reference, here's my current mdadm.conf:
>>>
>>>
>>> DEVICE /dev/sda1
>>> DEVICE /dev/sdb1
>>> DEVICE /dev/sdc1
>>> ARRAY /dev/md0 devices=/dev/sda1,/dev/sdb1,/dev/sdc1 level=5 
>>> num-devices=3
>>>
>>>     
>>
>> May I suggest:
>>
>>    DEVICE /dev/sd?1
>>    ARRAY /dev/md0 UUID=whatever
>>
>> it would be a lot safer.
>>
>>  
>>> I will be adding the devices /dev/sde1 and /dev/sdf1 (when I can find
>>> out how :)
>>>     
>>
>>  mdadm /dev/md0 --add /dev/sde1 /dev/sdf1
>>  mdadm --grow /dev/md0 --raid-disks=5
>>
>> NeilBrown
>> -
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>>   
> This might be an even sillier question, but I'll ask it anyway...
>
> If I add a drive to my RAID5 array, what happens to the ext3 
> filesystem on top of it? Does it grow automatically? Do I have to take 
> some action to use the extra space?
>
> Thanks
>
> Nigel
> -
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