Re: No md superblock immediately after creating RAID 5 /dev/md0

[Bernd Schubert <bs@q-leap.de>]

On Thursday 28 August 2008 10:32:32 thomas62186218@aol.com wrote:
> Hi all,
>
> I am struggling with an issue on an Ubuntu 8.0.4 64-bit system. The
> system has 12 SATA drives. I create a RAID 5 array using mdadm as
> follows:
>
> mdadm -Cv /dev/md0 -n12 -l5 -c128 /dev/sd[b-m] -R -f
>
> The device creates successfully and starts and is visible as syncing in
> cat /proc/mdstat. But, according to mdadm -X /dev/md0, there is no md
> superblock on the device. Doing the same mdadm -X command for all

You need to run --detail for md devices

> components /dev/sdb through /dev/sdm shows superblocks. If I reboot the

--examine only works for the components

> system, /dev/md0 is completely gone, and a mdadm --assemble --scan

Did you add the corresponding entries to your mdadm.conf?

See this chapter in "man 8 mdadm"

<quote>
         echo ’DEVICE /dev/hd[a-z] /dev/sd*[a-z]’ > mdadm.conf
         mdadm --examine --scan --config=mdadm.conf >> mdadm.conf
       This  will  find  arrays which could be assembled from existing IDE and 
SCSI whole drives (not partitions),
       and store the information in the format of a config file.  This file is 
very  likely  to  contain  unwanted
       detail, particularly the devices= entries.  It should be reviewed and 
edited before being used as an actual
       config file.

</quote>


Cheers,
Bernd


-- 
Bernd Schubert
Q-Leap Networks GmbH
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