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On 07/18/2011 11:08 PM, Jeff Cranmer wrote: |
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> Pardon my additional questions before taking the plunge here. |
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> |
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> So, given that I have three devices, /dev/sda, /dev/sdb and /dev/sdc, if |
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> I run the command mdadm --assemble --scan, would this find all the |
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> components and create a /dev/md0 disk without damaging the contents of |
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> the original RAID array? |
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If you've got the space and time, a backup can't hurt. Using --scan will |
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make it check the config file, but right now, there's probably nothing |
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useful in it. This looks like what you want to do to me: |
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If the --scan option is not given, then only devices and identities |
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listed on the command line are considered. |
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The first device will be the array device, and the remainder will be |
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examined when looking for components. |
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but I'd figure out where that md0 is coming from (below) first. |
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> The only item in /dev/mapper is th default 'control' entry. There is |
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> a /dev/md0 item already listed, but presently when I try to mount it, it |
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> reports that it is unable to read the superblock. Would the command |
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> above fix this? |
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Depends. Where'd the md0 come from? You probably have something in your |
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logs or dmesg, unless that device was created manually on your old system. |
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> Where is the config file mentioned in your e-mail, and do I need to edit |
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> it first to add the three raid disks? |
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It's /etc/mdadm.conf. You don't need it to create or use the array, but |
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you'll want to run mdadm when the machine boots and the config file |
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tells it what to do. Once the array is working, you can just do, |
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mdadm --detail --scan >> /etc/mdadm.conf |
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to populate it. I guess also check to make sure there's no default crap |
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in there these days. |