Manually-Confirgured Software RAID Under NT?

Mandoric asks: "I recently had a RAID-0 array die due to the controller refusing to recognize it as anything but a pair of single drives. Are there any software RAID programs (preferably under NT, as it's an NTFS partition I'd be restoring) that allow manual entry of a preexisting array's stripe size, rather than forcing all stripe data to be rewritten before reading from an array? Or ways to modify the volume data of an existing program to do this?" Are there decent RAID tools, for either NT or for Unix, that will allow one to recover from errors such as this?

Comments

spelling!!!

[Prowl]

conFIGured.

i know its petty but...

Re:One reason.

[dhopton]

This person wasnt using software. They were using Hardware based soltuon which subsequentially broke, and he's looking at a software based soltion to recover the data.

Recovering broken RAID

[sofar]

Well, it's probably not the easiest approach but one that is definately looking into IMHO:

- pop the disks into a linux or un*x system on a free controller port

- pop in an extra empty disk to salvage the data to. preferable larger than both disk together ;-)

- try to figure out the block size of the stripes (usually a multiple of 512 bytes)

- write a simple script that reads block n from broken RAID disk 1, and writes it to block 1 in the empty disk, then block 1 from broken RAID disk 2, to block 2 in the empty disk (ask your local unix guru)

You can fiddle with mount, df and cat /dev/hd?? > hexdump to see how data is arranged on the disks. Hardware RAID does usually not put special data blocks on the disks that make it unaccessible for these tools.

As an example, I run a software RAID and unmounted it cleanly, then remounted only one of both disks at the same point (so without the mirroring). Worked like a charm, also a nice way to continue working when one disk completely fails or you want to make copies fast ;-)

good luck

Raid 0?

[EvilOpie]

I am curious as to what the job of the server that the raid card was in was. After all, if he truly meant Raid 0, then that is striping without fault tolerance. If you had one drive fail, then the whole raid array would fail and he'd be in the same situation. Now there is an advantage in speed when it comes to drive access, but still, a single disk failure would take out the whole array. That is not unlike what happened here in that the raid array failed when the controller bombed.

That being the case, he should have backups somewhere to restore the data from. I wouldn't trust anything mission critical to a raid 0 array. Besides, when the controller went down, who's to say that it didn't basically shred the data on the disk apart? If the data is being spread across 2 disks, and now the computer sees them as two separate disks instead of one larger disk, then the data on the two disks is probably toast to begin with. (with the exception of going to those companies that do sector by sector data recovery from a hard drive for ungodly sums of money)

I guess the only thing I could suggest is to redo the server with Raid 1 minimum, and hope that your backups are good. There's no telling what that raid card did to your system when it failed.

Veritas can do this

[duffbeer703]

Veritas Volume Manager for NT/2000 can do this.

http://www.veritas.com/products/category/Product De tail.jhtml?productId=volumemanagerwin

Only one problem. It is very expensive.

Gonna mostlikey need somekind of hardware

[BenTheDewpendent]

Because your array was in hardware raid you may need to replace the the controller card. It may just get picked back up as it was if the drives or data didnt sustain any dammage.

use ghost or dd to back the contents of the drives up anyways incase the hardware solution has to re initialize the array from scratch.

you maybe able to find a controller that will work with software that can help fix your problem but i wouldnt count on software raid doing it.

shoulda used raid 0+1 maybe even 3 or 5

Here is an article

[Aknaton]

on Tom's Hardware entitled: "RAID without additional hardware: Do It Yourself With Windows 2000"

http://www4.tomshardware.com/howto/01q3/010906/i nd ex.html

For those of you who are scratching your heads ...

[NOT-2-QUICK]

Wondering what the hell all of this RAID stuff is about, don't worry...your plants are safe!!! To calm you further, I thought I would be generous and give you a brief description of the various levels.

But first, in case you road the "short bus" to school, we are not discussing the bug spray or what the Feds do to your dope stash... RAID is a commonly used acronym for Redundant Array of Inexpensive Disks!!!

Now, on to the various levels of RAID... The most common are as follows:

o RAID 0 : Striping without redundancy (a.k.a. no fault tolerance)
o RAID 1 : Transparent Mirroring
o RAID 3 : Striping with Parity for High Data Transfers
o RAID 4 : Striping with Parity for High Data Transfers
o RAID 5 : Striping with parity for High I/O transaction rates