[CentOS] doing a new install on top of existing software raid-1

Gordon Messmer yinyang at eburg.com
Sun Jan 22 03:49:14 UTC 2012

On 01/21/2012 05:52 PM, Les Mikesell wrote:
> I have moved raid sets to other machines (of similar distribution
> revs) and never had a problem before.

I wouldn't expect you to.  If you move volumes other than the boot 
volume, it doesn't matter that they get a new device name.

> In fact I have fairly regularly
> split raid1 volumes to different machines and re-synced with new
> mirrors and never had any surprises before.  The real issue with this
> box was that the disks are all swappable and I had used raid with
> autodetect specifically so I didn't have to track which disk was
> where.   And after booting the live dvd, they became more or less
> randomly named md devices, with each disk of the set becoming its own
> md device instead of pairing.  Recovering was fairly painful.

Well, you haven't given us enough information to really explain what you 
saw.  What I'd expect is that your MD devices were moved to /dev/md126, 
/dev/md127, etc.  Those names aren't random; they're sequential, 
reflecting the assigned device minor number starting at minor number 
126.  "dmesg" output might explain why the RAID sets weren't 
assembled... I've never seen that happen.

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