Re: mdadm can't reshape/resize arrays

[Goswin von Brederlow <goswin-v-b@web.de>]

"NeilBrown" <neilb@suse.de> writes:

> On Thu, June 25, 2009 1:03 am, Goswin von Brederlow wrote:
>> Hi,
>>
>> I'm trying to resize/reshape some of my arrays:
>>
>> md1 : active raid1 sdc5[1]
>>       9767424 blocks [2/1] [_U]
>>       bitmap: 48/150 pages [192KB], 32KB chunk
>>
>> % mdadm --grow --size max /dev/md1
>> mdadm: Cannot set device size for /dev/md1: Device or resource busy
>>
>> and dmesg says:
>>   md: couldn't update array info. -16
>>
>>
>> md2 : active raid5 sdc2[6](S) sde2[3] sdg1[1] sdf3[4] sdd1[5] sdb1[2]
>> sda1[0]
>>       945625280 blocks level 5, 64k chunk, algorithm 2 [6/6] [UUUUUU]
>>       bitmap: 0/181 pages [0KB], 512KB chunk
>>
>> % mdadm --grow -n 7 /dev/md2
>> mdadm: Need to backup 1920K of critical section..
>> mdadm: Cannot set device size/shape for /dev/md2: Device or resource busy
>>
>> and dmesg says:
>>   md: couldn't update array info. -16
>>
>>
>> % uname -a
>> Linux frosties 2.6.29.4-frosties-1 #8 Sun Jun 7 00:48:55 CEST 2009 x86_64
>> GNU/Linux
>>
>> % mdadm --version
>> mdadm - v2.6.9 - 10th March 2009
>>
>>
>> Anyone have an idea what is wrong there?
>
> md cannot grow arrays with bitmaps as it is not able to grow the bitmap.
> You need to remove the bitmap, grow the array, then add the bitmap.
> And unfortunately you cannot add the bitmap until the grow
> has finished.
>
> Yes, there is room for improvement here.
>
> NeilBrown

Most notably that mdadm catches that and gives a sensible error.

Thanks.

MfG
        Goswin