Clearing fakeraid information from a hard drive
Hello,
I have 4 hard drives that were previously in a fakeraid array on an Asus M2N-E in raid5. Because of this setup they now have fakeraid information somehow embedded into them. I was wondering if it is possible to clear this information from the drives? Fedora 8 keeps seeing an nvidia_ijifefdg array even after it has been removed from the system with nvidia chipset. The drives are now in a system with an Intel G33 based motherboard. |
You could try using dd to overwrite the entire drive with /dev/null or /dev/zero. For example, let's say the drives are sda, sdb, sdc, and sdd. For each drive:
dd of=/dev/null if=/dev/sda dd 0f=/dev/null if=/de/sdb dd of=/dev/null if=/dev/sdc dd 0f=/dev/null if=/dev/sdd Or, /dev/null could be replaced with /dev/zero. The dd command will overwrite the entire drive from MBR sector to the end, so you need to back up any information you want to keep. |
I tried using dd already, except i used /dev/urandom and just ctrl+c'd it after about 30 seconds, i figured the data would be at the beginning of the disk. I supposed it could have been at the end though.
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use dmraid; I believe it's dmraid -E, but check the man to be sure.
Edit: just looked it up; try dmraid -r first to identify the drive, then dmraid -rE {device identified by dmraid -r} to erase the data See http://linux.die.net/man/8/dmraid |
I believe RAID info is at the end of the drive because the MBR is at the front.
While I completely recommend mostlyharmless' advice -- use the right tool; if you want to experiment w/ dd, then you will need to find out how big the RAID/fakeraid info is. Here is a really brute force approach that I thought up, but didn't try. In fact, I wouldn't try it except as an experiment: This is using an old 60 GB drive as the hypothetical target. I figure that zeroing the last cylinder will kill the RAID info w/o destroying too much data. Code:
$ fdisk -l /dev/hda | head -4 If you know that you need to zero only the last sector, then a much safer, but more complicated, way would be to use the fdisk -l output to calculate the last sector: Code:
## using the same fdisk info I did re-read the dd man page; but since I didn't try this, I can't be sure that my seeks aren't off by 1 because either dd or fdisk numbers from 0. |
Couple of things you can do:
1. if devices are partitions, just delete the fd type partitions using fdisk 2. if devices are whole luns/drives, zero the last 128k of the drive with dd, that's where the raid superblock is Hope this helps. |
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