CentOS - Jan 2010 - raid1 creation :: not large enough to join array

Hi!
I have 2 identical hdd (1002FBYS) with the same firmware, etc .. really
identical! when i try to add the second hdd to this raid1 array i have
the message that /dev/sdb is not large enough to join array!!
on the first hdd i have 100 mb unpartitioned at the end of disk (as i
understood that mdadm put there some info...)
Anyone, any idea what can be wrong? i already done this procees several
times and this is first time i encounter this and i have no idea what
can be the problem ..

Thanks!
Adrian
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On Jan 16, 2010, at 10:27 AM, Adrian Sevcenco  
<Adrian.Sevcenco at cern.ch> wrote:
> Hi!
> I have 2 identical hdd (1002FBYS) with the same firmware, etc ..  
> really
> identical! when i try to add the second hdd to this raid1 array i have
> the message that /dev/sdb is not large enough to join array!!
> on the first hdd i have 100 mb unpartitioned at the end of disk (as i
> understood that mdadm put there some info...)
> Anyone, any idea what can be wrong? i already done this procees  
> several
> times and this is first time i encounter this and i have no idea what
> can be the problem ..
Make sure the partitions are exactly the same, you can use sfdisk to  
copy the table from a to b.

-Ross

----- Original Message ----
> From: Adrian Sevcenco <Adrian.Sevcenco at cern.ch>
> To: CentOS mailing list <centos at centos.org>
> Sent: Sat, 16 January, 2010 15:27:12
> Subject: [CentOS] raid1 creation :: not large enough to join array
> 
> Hi!
> I have 2 identical hdd (1002FBYS) with the same firmware, etc .. really
> identical! when i try to add the second hdd to this raid1 array i have
> the message that /dev/sdb is not large enough to join array!!
> on the first hdd i have 100 mb unpartitioned at the end of disk (as i
> understood that mdadm put there some info...)
> Anyone, any idea what can be wrong? i already done this procees several
> times and this is first time i encounter this and i have no idea what
> can be the problem ..
> 
> Thanks!
> Adrian
Last time I got this, it was because I was trying to add the whole disk
(/dev/sdb) rather than the partition /dev/sdb1. I don't know enough about
what you are doing or RAID for that matter to know if that is exactly what you
are doing, but it may help.

Regards,

Ian.