How to determine if Knoppix can read my Raid 0

[Ravis]

In brief, my story first:

A week ago I knew nothing about Raid.... Unfortunately, now I know a little bit more

What happened was that I got a warning in WinXp SP2 saying that something was about to happen. I was instructed to update my backup immediately, wich I did(photos and my database managing these). I went to bed and the next day my computer did'nt start and now I'm seeking for a way to rescuee my "nice to have" documents and files.

I put in a new 500gb sata disk, but I do not know if Knoppix (5.1) is able to write to it, wich I intend to do. I used gparted to format it(fat32), but I'm not sure if I did this correctly. However, Knoppix reckognize this disk as /dev/sdc

Before I try to use dd_rescue, wich I have read a lot about(still not sure if understand all this), I would like to know if there is a way for me to determine if knoppix is able to read my Raid 0 array(2x250gb sata ntfs). The s.m.a.r.t report from dell, hidden under the F12 button somewhere, revealed that about 30 blocks was unreadable. Everything before and after was read successfully.

So, is there a way for me to determine if Knoppix is able to read the Raid 0 array? If it can, I guess I can use dd_rescue to write to my new 500gb disk.

Any help is really appreciated!


Btw, would it make sense to disconnect the two 250gb disks, put my new 500gb drive on top of the boot list in Bios, install WinXp again and then use Windows software to do the recovery?

[Harry Kuhman]

Btw, would it make sense to disconnect the two 250gb disks, put my new 500gb drive on top of the boot list in Bios, install WinXp again and then use Windows software to do the recovery?

Yes, that would make sense. I'm honestly amazed by how many people come to this forum and indicate that they had no idea that a Windows based RAID disk suystem would be hard to recover files from with Linux. How do people get in this position? Did a small shop sell you a system already configured as a RAID system, then wash their hands of you when you tried to get suppor? Did you just choose to to build up a RAID system yourself for the extra speed, and completely ignore the need for good backups, and if so how did you even find out enough to configure your system as RAID zero without realizing that if either disk fails you loose everything on both disks (instantly doubling your chance of failure) and at the same time making it near imposable to recover the data with a non-Windows system?

You system is almost certainly software based RAID and relies on special disk drivers that are written to work with Windows. While there are Linux Raid systems that support RAID 0, Raid 1, RAID 5 and other RAID configurations, there is no reason to expect that they lay down the data exactly as a Windows system would, and if they do not then the array will at best not be recognized and at worst destroyed when you try.

Reinstalling Windows on the new drive (non-raid configuration), then installing the RAID drivers and trying to access the older drives as a RAID array would seem to be your best bet. Be warned, sometimes Windows mucks up a partition so bad that it can't access the files any longer, and sometimes it mucks up a partition so bad that Knoppix can access the partition either. Given that Windows will muck up a normal partition, I certainly expect that it can muck up a RAID array just as badly. If you do manage to read the data, I suggest considering recovering the desired files to the new disk, then seriously thinking about if you want to keep the 2 older disks as a RAID array or use them as 2 additional independent disks.

[Ravis]

Thanks a lot for a very good answer!

Yes, I'm just an ordinary user that knew nothing about Raid when I bought my computer. Dell sold it to me with this configuration and I was'nt aware of the danger. I would certainly not choose speed over security, so from now on I will keep th OS and SW on one drive, and keep my data on the second and third. Perhaps I will set up the two 250gb as Raid 1 for redundancy purposes and keep my data on my new 500gb disk.

I'll never use Raid 0 again, and if I come across anyone using this system, I will certianly advise them to change.

Thanks again!

Must admit I'm impressed with Knoppix, and I'm new to Linux just seven days ago. Iv've learned a lot this week ;D

[Harry Kuhman]

... Perhaps I will set up the two 250gb as Raid 1 for redundancy purposes and keep my data on my new 500gb disk.

I'll never use Raid 0 again, and if I come across anyone using this system, I will certianly advise them to change.

Thanks again!

Must admit I'm impressed with Knoppix, and I'm new to Linux just seven days ago. Iv've learned a lot this week ;D

RAID 0 may have some valid uses where performance is much more important than the data itself (such as for a swap file), but in most cases it's a mistake.

Setting up the 2 older drives as a RAID 1 system could help protect data, as too many people never do critical backups and come here only after the data is gone. But be aware that RAID 1 only backs you up as far as a hardware failure of one of the drives goes. It does not protect you at all from user error, virus or other malware, Windows data corruption, or program bugs that destroy data. In those cases whatever is written to one disk is quickly written to the other as well. Nor will it protect your data from problems like power surges or case over heating (I have a friend who trusted RAID 10, only to have all data lost when the case fan failed and the drives quickly overheated!). And in your case you seem to be planning on RAIDing the operating system, not the usually more critical data. If you don't yet have a reliable way to back up your data, I might consider using one of the older drives purely as a backup copy of the data, as opposed to a Live RAID 1 array of the OS. You might even want to mount the drive in a removable internal tray such as this (link is just an example, not a recommendation to use this particular one or this vendor) so that it was only in the computer when making backups, then could be put safely away or even moved to a different location so that your backup was safer.

[Ravis]

Thanks again for an excellent answer. What can I say? THANK YOU!