Re: cannot add device to partitioned raid6 array

["Florian D." <flockmock@gmx.at>]

Neil Brown wrote:
> On Saturday March 31, flockmock@gmx.at wrote:
>> hi list!
>>
>> in short:
>> I created a partitioned raid6 array with 2 missing drives. Now, I want to add a device. It fails with:
>> flockmock ~ # mdadm -a /dev/md_d4 /dev/sdb2
>> mdadm: add new device failed for /dev/sdb2 as 4: Invalid argument
> 
> Thanks for the detailed problem report.
> 
> I think the cause of the error is that /dev/sdb2 is too small.
> It needs to be at least 490030594 sectors. How big is it?

but the *device* size should be only ~250GB, so the array size is ~500GB, no?

flockmock ~ # mdadm --detail /dev/md_d4
/dev/md_d4:
         Version : 00.90.03
   Creation Time : Sat Mar 31 19:48:58 2007
      Raid Level : raid6
      Array Size : 490030464 (467.33 GiB 501.79 GB)
   Used Dev Size : 245015232 (233.66 GiB 250.90 GB)
                   ^^^^^^^^^^

these disks are all 250 GB harddisks, formatted in the same way -- but they are from different 
vendors! The block sizes from the partitions vary a little bit (taken from /sbin/fdisk):

/dev/sda2: 245015347
/dev/sdc2: 245015347
/dev/sdb2: 244099642  -> different vendor

do you think that may be the cause?

thanks a lot,
florian