Re: 16 HDDs too much for RAID6?

[Luca Berra <bluca@comedia.it>]

On Thu, Mar 06, 2008 at 05:16:21PM +0100, Andre Noll wrote:
>On 11:55, Lars Täuber wrote:
>> monosan:~ # cat /etc/mdadm.conf 
>> DEVICE partitions
>> ARRAY /dev/md2 level=raid1 UUID=d9d31de2:e6dbd3c3:37c7ea09:882a64e5
>> ARRAY /dev/md3 level=raid1 UUID=a8687183:a79e514c:ca492c4b:ffd4384f
>> ARRAY /dev/md4 level=raid6 num-devices=16 UUID=8d596319:4d21dba3:3871bccf:5b90a66d
>
>Does it help to list only the 16 devices that are used for the array,
>i.e. something like
>
>	DEVICE /dev/sd[a-p]

i hope kernel will pevent you from doing something this stupid, but i am
not that sure.
if you wanna check if the problem is device selection a more appropriate
line would be
DEVICE /dev/mapper/mpath*
or
DEVICE /dev/dm-[0-9] /dev/dm-1[0-5]

>I think this is what is confusing mdadm. Your "DEVICE partitions"
>line instructs mdadm to consider all devices in /proc/partitions,
>so it finds both sdy and sdi.
in this case i believe the error message would be different

>> Is there a way to get more verbose infos or debug this anyhow?

you could try with the --verbose option and post the results here.

also could you check if the minor number of /dev/dm-* are really unique?

in case this yelds no result we will have to add some more printf in
Assemble.c.

Regards,
L.

-- 
Luca Berra -- bluca@comedia.it
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