Ubuntu – Read a Single MDADM RAID 1 Disk from Software RAID Array

regardless of any controller/driver

Disregarding RAID implementation? Then the answer should generally be no: you can not assume that all hardware controllers treat disks in such a transparent way.

However, in the case of software raid in Linux (md+raid1) then yes, there's no disk header or secret block-level optimization going on there.

In the case of Disk Mirroring in Windows, it involves the disk having been initialized as "Dynamic" and, well, should just work, given that the system that reads it can understand the dynamic volumes - in other word it will most likely only be accessible from another system running Windows.

In the end; you can try connecting the disk regardless of controller. If it works, it works. No controller will damage the data on the disk as long as you don't tell it to - i.e. as long as you don't execute an operation such as "initialize" or anything.

Is it possible to clone the individual disks of a hardware RAID to get a copy of the contained array?

yes, it is possible to copy individual disks. Regardless if they are part of a RAID array or not. Just power the computer with the drives in it down, move the un-powered drive to another computer ^* and copy it.

There are many methods to do the last. Some of them are:

• Full disk image (e.g. with Norton Ghost)
• Full disk image (e.g. with Acronis)
• A simple dd, cat or cp of the whole drive (any unix like OS, either installed or from a LiveCD/LiveUSB.

Any of those will do as long as the disk you are copying is not in use.

You can even read from the disk and store the copy somewhere on the network (e.g. use cat piled though netcat).

I have an Adaptec RAID controller. I put it offline, attached the raid members HDDs to a regular SATA port and tried to clone the disks to some other disks using G4L (http://sourceforge.net/projects/g4l/) using the RAW mode. It looked like the clone process did work (amount

According to your link g41 supports raw copies of whole disks. That should have worked.

of data copied), but after I used the cloned disks on the Adaptec RAID controller, it did not find any arrays (but did detect the disks).

Dis you copy to identical disks? (Read: Did you copy to disks with the precise same size? Copying from 2TB to 2TB (with the second 2TB being a few KB smaller) might cause lots of problems if there is data in the last sector of the disk.

Vice versa: larger disk might also cause problems for the same reason.

So I wonder if it is even possible to clone the disk or if there is some data that has to be copied in another way?

A 1:1 raw copy to a identical disk should work.

it is a weird way to copy data though. Normally you would just create a second RAID array (or wipe and restore the original RAID) and restore the data from backups.

This leads me to the idea that you have "problem X" and that you are trying to solve that by "method Y". That might work but adding why you want to do this strange thing might help a lot.

^*: The reason to use another computer is that the RAID card might detect that a drive has been removed and drop it from the array. Thus power it down, remove the drive, copy the drive and place it back before powering on the RAID card.
(Unplugging the RAID card might also work).