From mboxrd@z Thu Jan  1 00:00:00 1970
From: Benjamin ESTRABAUD <be@mpstor.com>
Subject: Re: Readding a drive fails because of wrong size?
Date: Fri, 26 Jun 2009 13:02:35 +0100
Message-ID: <4A44B8DB.3010906@mpstor.com>
References: <4A43C8C7.7000209@canbytel.com>
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Sender: linux-raid-owner@vger.kernel.org
To: Scott Baker <bakers@canbytel.com>
Cc: linux-raid@vger.kernel.org
List-Id: linux-raid.ids

Hi,

I had exactly the same issue, which only occurs when you are using 
multiple RAID, and will only occur on mdX for X>0.

In my case it turned out that the checkMinSize algorithm (I can't recall 
the exact name), was always using md0's minimum component size as a 
reference, even when checking for the minimum component size of md1, 
md2, md3, etc...

This turned out not to be a mdadm bug but rather the fact that I was 
using a custom "MdpMinorShift" value (look in md.c), which was then 
different than the hardcoded mdadm one.

Changing the one in mdadm to match the one I had in md.c worked fine then.

Are you using a different MdpMinorShift value?

Ben - MPSTOR.

Scott Baker wrote:
> I have a four disk RAID5 array, and one of the HDs got removed from 
> the array. All four drives are identical in size and partitioning.
>
> -------------------------------------------------------------------------- 
>
>
> Disk /dev/sdc: 500.1 GB, 500107862016 bytes
> 255 heads, 63 sectors/track, 60801 cylinders
> Units = cylinders of 16065 * 512 = 8225280 bytes
>
>    Device Boot      Start         End      Blocks   Id  System
> /dev/sdc1               1       60801   488384032   fd  Linux raid 
> autodetect
>
> Disk /dev/sdd: 500.1 GB, 500107862016 bytes
> 255 heads, 63 sectors/track, 60801 cylinders
> Units = cylinders of 16065 * 512 = 8225280 bytes
>
>    Device Boot      Start         End      Blocks   Id  System
> /dev/sdd1               1       60801   488384032   fd  Linux raid 
> autodetect
>
> Disk /dev/sde: 500.1 GB, 500107862016 bytes
> 255 heads, 63 sectors/track, 60801 cylinders
> Units = cylinders of 16065 * 512 = 8225280 bytes
>
>    Device Boot      Start         End      Blocks   Id  System
> /dev/sde1               1       60801   488384032   fd  Linux raid 
> autodetect
>
> Disk /dev/sdf: 500.1 GB, 500107862016 bytes
> 255 heads, 63 sectors/track, 60801 cylinders
> Units = cylinders of 16065 * 512 = 8225280 bytes
>
>    Device Boot      Start         End      Blocks   Id  System
> /dev/sdf1               1       60801   488384032   fd  Linux raid 
> autodetect
>
> -------------------------------------------------------------------------- 
>
>
> /dev/sde1 needs to get added back into the array, the other three 
> drives are fine.
>
> -------------------------------------------------------------------------- 
>
>
> /dev/md8:
>         Version : 00.90.03
>   Creation Time : Fri Oct 26 16:00:51 2007
>      Raid Level : raid5
>      Array Size : 1465151808 (1397.28 GiB 1500.32 GB)
>   Used Dev Size : 488383936 (465.76 GiB 500.11 GB)
>    Raid Devices : 4
>   Total Devices : 3
> Preferred Minor : 8
>     Persistence : Superblock is persistent
>
>     Update Time : Thu Jun 25 11:27:31 2009
>           State : clean, degraded
>  Active Devices : 3
> Working Devices : 3
>  Failed Devices : 0
>   Spare Devices : 0
>
>          Layout : left-symmetric
>      Chunk Size : 64K
>
>            UUID : 44c3189a:58ffab82:c2c79482:d044a0fb
>          Events : 0.218148
>
>     Number   Major   Minor   RaidDevice State
>        0       8       33        0      active sync   /dev/sdc1
>        1       8       49        1      active sync   /dev/sdd1
>        2       0        0        2      removed
>        3       8       81        3      active sync   /dev/sdf1
>
> -------------------------------------------------------------------------- 
>
>
> But when I try and add it to the array it gives me a array that the 
> partition isn't big enough? Nothing has changed, I haven't formatted 
> or anything. All I did was replace a SATA cable and now I can't add 
> that drive back to the array? This server is running CentOS 5.3 with 
> all the updates.
>
> -------------------------------------------------------------------------- 
>
>
> :./mdadm /dev/md8 --add /dev/sde1
> mdadm: /dev/sde1 not large enough to join array
>
> root@white(/tmp/mdadm-2.6.9)
> :mdadm --version
> mdadm - v2.6.4 - 19th October 2007
>
> -------------------------------------------------------------------------- 
>
>
> HELP!
> -- 
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