Re: Replacement RAID hard drives - do they have to be "clean"?
Ken Heard <kenslists@teksavvy.com> writes:
> One of my boxes has a RAID1 using two Seagate SATA 3.0 1 tb hard drives.
> I need to replace one of them, and I would like to use as a replacement
> a Samsung SATA 2.0 1 tb drive which already has on it data which I do
> not need to keep.
>
> My first question is: although both drives are the same size, can I get
> away with having one drive a Seagate 3.0 and the other Samsung 2.0?
That depends on your RAID controller.
> It occurred to me that if I made the change described in the first
> paragraph -- but without somehow making the data already on it
> unreadable -- there would be a different data set on each drive; so that
> the RAID1 software would not necessarily know which drive should be the
> data source to copy to the other drive. It also occurred to me that the
> software could combine the data on each drive, so that both drives would
> have both data sets.
That depends on your RAID controller. It's probably a very good idea to
"clean" the drive before plugging it in. "Clean" the drive would mean
to use something like dd to overwrite the whole drive with zeroes.
> I consequently assume that the data on the replacement drive must
> somehow be made unreadable. Is that assumption correct? If so, do the
> data have to be "shredded", or is it sufficient simply either to
> "delete" them or simply reformat the drive?
To actually delete all data on a disk beyond all recoverability, you
basically have to melt down the drive. Modern drives usually don't
allow you to format them.
> Finally, once I have a "clean" new drive installed, will the RAID1
> copying process partition the new drive the same way as the other drive
> and copy the files without further human intervention?
That depends on your RAID controller. At least it should rebuild the
RAID once you told it to use the disk as a replacement for the old one.
--
Knowledge is volatile and fluid. Software is power.
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