[ale] Just an FYI share

[Wolf Halton]

disks that mate for life?

Wolf Halton
--
http://wolfhalton.info
Apache developer:
wolfhalton at apache.org
On Jun 30, 2013 9:45 PM, "JD" <jdp at algoloma.com> wrote:

> Your experience is seen a few times every month on the Ubuntu Forums.
>
> RAID tools, definitely mdadm, leave RAID information on the drive in the
> form of
> a superblock, so to reuse a drive, we need to remove that "RAID" tag from
> the
> physical disk.  I think mdadm has an option to do it, though I've never
> had an
> issue reusing former mdadm RAID HDDs in other systems.  --zero-superblock
> seems
> to ring a bell for me.  As usual, check the man page for your specific
> installed
> tools.
>
> OTOH, some disks like each other and really, REALLY want to stay together.
> Seems
> sorta cool that they try so very hard. Huh?
>
>
> On 06/30/2013 09:31 PM, Chuck Payne wrote:
> > If you are like me and recycle things when you can. One thing to watch
> > out for, that I never thought to check on. What is really written to a
> > hard drive.
> >
> > I had a NAS die a while back, that left me 5 health drives. While
> > upgrading my server, I used one of the drives to replace a failed
> > drive in my server.
> >
> > Well when I went to write the file system for the drive, I kept
> > getting a very strange error, that the new drive was in use by the
> > system.  "WTF!", how can this be? I ran fdisk and gparted. Both
> > partition the drive correct but when I when to write the file system.
> > Again, I got the error that the drive was in use.
> >
> > I reboot changed how my SATA drive acted from IDE to ACHI, since I
> > don't have any more IDE in the server.  I tried again. Same error.
> > Well I looked in dmesg saw the drive, but I saw that the first slice
> > was in use by soft raid  (md).  Say what? Sure enough I cat /proc/md
> > and there it was. Again, excuse the use, but "WTF!".
> >
> > When the distro I use, did a scan for existing partitions. I thought I
> > had blasted all the partition, the showed was using XFS /dev/sdx1, but
> > there was a hidden partition. One the OS picked up on, but fdisk and
> > gpart did not. The partition, I found out was where the raid wrote the
> > it information, it showed up as MD-512 on my partition tool.
> >
> > I used the partition tool that comes with my distro to remove the
> > hidden partition and I am able to use the drive.
> >
> > I wanted to share this because, to this day I haven't seen this. My
> > distro saw that hidden partition and thought, ok there is a soft raid,
> > lets set it up, even though there the other four drives were missing.
> >
> > So I guess next time I recycle a drive, I will use a nuke program and
> > not hope that fdisk or gparted will get the drive done because it
> > didn't this time.
> >
> > I wanted to share this just in cause anyone else hits a drive that you
> > can't write too, that you just add to a system.
> >
> > I am not sure if this part 3.x kernel.
> >
> > Any thoughts? Feed back is welcome.
> >
> > --
> > Terror PUP a.k.a
> > Chuck "PUP" Payne
> >
> > (678) 636-9678
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