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Daniel
Asked: 2012-12-22 12:29:23 +0800 CST

mdadm: Disk configuration by UUID

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I want to create a soft RAID-5 and use UUIDs im the mdadm config file. So I have four disks with 1 partition each that spans the whole disk. But since the partitons don'5 have a filesystem, blkid does not give a UUID. Is there a way to do that?

linux

3 Answers

  1. Best Answer

    You first create the RAID5 device and then use the UUID of it in your mdadm.conf, not the UUID for a filesystem:

    # mdadm --detail /dev/md0
/dev/md0:
        Version : 1.2
 ....
           Name : enterprise:0  (local to host enterprise)
           UUID : 7d2bf7e5:dc6edd5c:3ca12e46:8c9e5d4b
         Events : 48

    Number   Major   Minor   RaidDevice State

    So I have a mdadm.conf of

    ARRAY /dev/md/0 metadata=1.2 UUID=7d2bf7e5:dc6edd5c:3ca12e46:8c9e5d4b name=enterprise:0
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  2. Use the entries in /dev/disk/by-id to reference the parts of the RAID. For example:

    /dev/disk/by-id/ata-ST9320423AS_5VH56VSB

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  3. First create your desired raid array with mdadm command. As soon as this is done you will have a UUID for the md. Then you can create a mdadm.conf with

    mdadm --examine --scan > /etc/mdadm.conf

    Verify later on with ls -l /dev/disk/by-uuid/

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