Problem creating software raid - Device or resource busy.

Hi,

Re: Software Raid Problem
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Background
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OS= Opensuse 10.2
2 X 250gb Sata drives

Drive 1
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/dev/sda1 = swap
/dev/sda2 = linux raid (os & data is here)
/dev/sda3 = linux raid

Drive 2
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/dev/sdb1 = swap
/dev/sdb2 = linux resiser
/dev/sdb3 = linux reiser
---------------------------------------------------------------

Using mdadm I managed to create /dev/md0 in raid 1 (mirror). /dev/sda3 & /dev/sdb3 where added to this set.

Good so far....now for the problem....

Problems Area
-----------------------
Using mdadm I failed to create /dev/md1 in raid 1 (mirror). /dev/sda2 & /dev/sdb2 where part of this set.
I get this error: mdadm: cannot open device /dev/sda2: Device or resource busy.

I booted from rescue CD, and ran the mdam command to create /dev/md1 ... and it worked! I let the raid sync.

When I reboot, I get this error:

mdadm: cannot open device /dev/sda2: Device or resource busy.
mdadm: /dev/sda2 has no superblock - assembly aborted

How to do I solve this?

Your help will be appreciated.

Regards

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Hi

I'm not familiar with your kernel or mdadm versions - please say.

Are you describing partition types here (ie 0xfd = raid autodetect in fdisk)?

Do you mean you actually have live filesystems here?

You seem to indicate that there are filesystems on disk 2 but none on disk 1. Yet you say "os & data is here" ? What do you mean by that?

Please show:
* partitions of both disks
* existing filesystems on both disks

FYI A raid device is usually made from empty partitions (devices) and you create a new filesystem inside the raid device. You can't usually just 'raid' them after the fact.

What command?

That would make sense - but a normal md device has a superblock and this would overwrite bits of your filesystem if you already have data on the disk. That is bad.

hmmmm.... debatable :)

yes. It sounds like you've got some confusion about creating a mirrored filesystem. I suspect you have a mounted filesystem on /dev/sda2

Have a look at the FAQ stuff here:
http://linux-raid.osdl.org/

Well, it would :)
The rescue system won't have mounted anything.

I think you need to:
* repair any damage to your data
* prepare your kernel and init system
* go to a rescue system
* create a 'broken' mirror using your empty disk (disk2?).
* make a filesystem on the broken mirror
* copy the good filesystems to the broken mirror
* add the now free partitions from disk1 to the broken mirror
* wait for a resync
* reboot

David