Lik`s forum

[lik]

Members of dmraid arrays (block and software RAID devices) contain metadata signatures which are used to discover/assemble target RAID sets.

To remove them and release undelying block devices one should erase metadata signatures.

Discover all software RAID devices supported on your system, eg:

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# dmraid -r
/dev/dm-46: hpt45x, "hpt45x_chidjhaiaa-0", striped, ok, 320172928 sectors, data@ 0
/dev/dm-50: hpt45x, "hpt45x_chidjhaiaa-0", striped, ok, 320172928 sectors, data@ 0
/dev/dm-54: hpt45x, "hpt45x_chidjhaiaa-1", striped, ok, 320172928 sectors, data@ 0
/dev/dm-58: hpt45x, "hpt45x_chidjhaiaa-1", striped, ok, 320172928 sectors, data@ 0


If {-E| --erase_metadata} is added to {-r| --raid_devices} the RAID metadata on the devices gets conditionally erased:

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# dmraid -rE
Do you really want to erase "hpt45x" ondisk metadata on /dev/sdb ? [y/n] :y
...
...

And then remove logical devices which use device-mapper driver:

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# dmsetup remove /dev/mapper/hpt45x_chidjhaiaa-0
...
...

[lik]

As one of the possible workarounds one can use the following commands to overwrite (read ! destroy !) RAID metadata which is stored on the HDD:

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dd if=/dev/zero of=/dev/sda bs=512 count=8196
dd bs=512 if=/dev/zero of=/dev/sda count=8196 seek=$((`blockdev --getsz /dev/sda` - 8196))