Question about RAID set names

Luca Berra bluca at
Thu Sep 23 06:09:14 UTC 2004

On Wed, Sep 22, 2004 at 01:50:46PM -0700, Jane Liu wrote:
>And what's the relationship between /dev/mapper and /dev/dm-* devices? I
>noticed that when an array, say, /dev/mapper/nvraid_abcdefgh is
>activated, a /dev/dm-0 also appears. I can run fdisk and mkfs, etc. on
dm-<minor> is the sysfs name for the device-mapper devices the number is
the minor number of the device. I believe you have something which is
dynamically creating device nodes based on sysfs (devfs? udev?).

>both of them. After reboot, /dev/mapper/nvraid_abcdefgh still exists but
>cannot be opened, where as /dev/dm-0 no longer exists. After running
the dm device has not been activated

>dmraid -ay, /dev/dm-0 appears again. If I change the RAID set name to
>"nvraid_blah", then running "dmraid -ay" creates /dev/mapper/nvraid_blah
>as well as /dev/dm-0. So it seems that /dev/dm-* enumeration is
>independent of the RAID set names. Does that mean it's OK to change the
>RAID set name during the lifetime of the set? 
how did you rename the array?

Luca Berra -- bluca at
        Communication Media & Services S.r.l.
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