Accessing RAID 0 from Knoppix

[forager]

I have successfully read a striped config of two RAID 0 discs (Windows XP) using
Knoppix 5.1.1. This version very nicely auto-mounted the partitions and I was
able to easily see the C:\ drive. Point and click.

Two questions:

1) I had started with the latest version of Knoppix 6.0.1 before I went backward to 5.1.1.
With 6.0.1, the auto-mounting of RAID discs is not performed. Is there a reason for this,
given that this functionality is highly desirable? I'll continue, I suppose, to use 5.1.1 for
the time being.

2) Can anyone suggest what mount commands are being used in 5.1.1 in case I wanted to
use the latest 6.0.1 version of Knoppix ?

I've scoured the lists and seen many posts relating to this subject, but haven't seen a clear
method. For example, the use of "dmraid" is suggested, Once dmraid is used, what are the
"mount" instructions? Is a directory "/dev/mapper" always created?

Thanks!

[Harry Kuhman]

You likely are not goig to read a raid 0 driver with Knoppix. Most RAID systems used by home users depend on a special software raid driver to get the RAID functions. More often than not that raid driver is only available for windows.

If you have a true hardware RAID system then Knoppix may be able to see the raid drive, assuming that the Microsoft software hasn't otherwise damaged it. And with a few add-in software RAID cards you can get software for some distros of Linux (often Red Hat and Suse). You might be able to use these to read the RAID system, but getting the drivers installed in Knoppix may be a challenge.

Linux does have its own RAID support for a number of RAID types including Raid zero, but unless the drive geometry just happens to lay out exactly the same way that the Proprietary Windows system geometry does, that is not going to help you and trying to use it may make things a whole lot worse.

You may think that you see the file system of a RAID 0 drive in Knoppix, but if this happens it is only because you are picking up the portion of the main partition file table that is stored on the first drive (and in most cases it will all fit on the first raid drive for the top level directory). But Since Knoppix only sees this as a simple drive and not a RAID system, the file pointers are interpreted incorrectly and they don't end up pointing to the actual data,.

RAID 0 of course has no redundancy, and actually increases your chance of data loss, since either hardware drive failing will cause a complete loss of data on both discs, as will any Windows based corruption of either disk. And usually the RAID software adds enough extra overhead that any performance improvement is not worth it. There are some cases where raid might be justifiable, such as extensive video work on large files including editing and conversions, where the final data will not be stored on the RAID system, it is only used for intermediate storage. But for most users, choosing to use RAID 0 is a mistake.

And, while this does not relate to your problem, let me also mention that using RAID 1 with 2 redundant drives (or any redundant RAID system) is not an acceptable alternative to having data backups. Many things can destroy the data on both drives, including viruses, power supply or fan failures, operator error, program error, or just good ol' Microsoft going Hasta-la-Vista with your data.

[forager]

Thanks for this general RAID feedback. However, Knoppix 5.1.1 successfully reads the
entire RAID 0 C: partition by auto-mounting it. The files are there and complete.
I had a few non-essential but useful files to copy from C:, but was pleasantly
surprised when Knoppix 5.1.1 performed its auto-mount function.

The questions are: 1) why doesn't the most recent version (6.0.1) have the same auto-mount
functionality as 5.1.1, and 2) what might the mount commands be that 5.1.1
is using (but are buried under the user interface)? Maybe there is a log of 5.1.1's
mounts when it launches its desktop?