Raid 5 array lost

Beaucairej
Beaucairej used Ask the Experts™
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I have a customer built machine with an 80GB drive for the OS and 4 320GB Drives in a Raid 5 Array.  After recovering from a power falure, I am not able to get the raid array working.  In the My Computer screen it shows a Drive D: but when I go to access the drive I get Drve D:\ is not accessable.  The file or directory is corrupted and unreadable.  When i first boot the machine I get the messages that the drives are all there but cannot access the drive.

How to I get the raid array back without distroying the data?
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Need more info:

1. What controller are you using or is this software RAID?
2. Have you completed a verify media test of any type on the drives?
3. Do you know the specific parameters the RAID volume was created with?

It sounds as though your RAID table has either been lost or corrupted. This can be recovered but I need more information so I can tell you which steps you should take and in which order.

Commented:
You need to get into the RAID BIOS and check the status of the virtual drive. It looks like you lost more than one physical drive in the array, RAID 5 can limp along with only one failure.
Sometimes a drive can go offline for no apparent reason - you can online it and rebuild the array. If more than one drive is permanently failed, you will have  to replace them, reinitialize the array and restore from backkup.
since the drives show up and windows see's it as a harddrive. you can try to run chkdsk d:\ and see if windows can fix it.

chkdsk d:\ - just scan the drive
chkdsk d:\ /f will try to fix it.
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Or, run getdataback on the drive to recover the data to another source and just reformat it.
@ all - Guys these are all great steps to take at certain points but at this time there are some BIG unknowns which could make enormous differences in outlining the correct recovery procedures for this particular case.

I would implore you all to slow down and not blurt out possible solutions. A step by step approach to data recovery is imperative He could lose client data here and that is the only thing worst than losing your own data.
noxchoIT Product Manager
Top Expert 2009

Commented:
Do not run CHKDSK D:/f on that drive cause it could damage data. CHKDSK is a known data killer.
First of all see in Windows Disk Management if the file system of D: drive is detected or not. If yes then try taking ownership of the drive.
Then try to use either GetDataBack www.runtime.org or Drive Backup 10 trial - Volume Explorer from here: www.drive-backup.com
Both can help to recover the data.
If you start the last one and close it then find STUBACT.log file in Drive Backup 10 root folder then I could look if the problem is in drive geometry.
To add to noxcho's steps. You may also want to acquire a copy of Raid Reconstructor as well. It is very possible with the power outage that there was a write back failure which caused a corruption in the RAID table. RAID Reconstructor can rebuild this table without causing data loss. This will most likely be a necessary step to take prior to running GetDataBack.

Raid Reconstructor (also from our friends at Runtime): http://www.runtime.org/raid.htm 

Commented:
@ All:
What kind of raid is it? Do you have a hardware raid controller? Or did you use windows to create a software raid?
Before that is clear no answer or advise is possible.
In other words can we get my first post answered?

Author

Commented:
Guys;  thanks for all the suggestions:

SemperWiFi:  The RAID Controller is software Raid using the Intel 82801GD/GH SATA RAID Controller
What do you mean "Do you know the specific parameters the RAID volume was created with?"  I know it was created when I first installed the OS. there are 4 380 GB Seagate Drives in the Array & it shows up as one 500.  It shows up in Device manager as an ST380811AS and in the Disj Manager it is shown as DISK 1 with 465.75GB Capacity and 190.4GB free.  Is there is any other information you need from me?

On Startup I can see all 4 drives being recognized in the BIOS as individual drives in the Array.
Two questions Beaucairej,

1. When you installed the OS, were you required to install RAID drivers?

If yes, then this is in fact hardware RAID. I believe I know the answer to this question already but want to make sure.
Sorry that was one question... in my defense it is VERY early ;-)

Author

Commented:
SemperWiFi:  Yes, i believe I did have to install drivers from a floppy disk.
OK, this means you are actually in fact using hardware RAID.

The simple fact with RAID recovery even 'non-destructive' recovery methods can still be destructive. This being the case the first step is and should always be to backup the RAID set prior to any recovery attempts.

Backing up your RAID set can be done by using a DOS based bit level imaging utility of your choice. Another option is an application like RunTime's RAID Reconstructor which allows you to reconstruct a RAID array and image out to another single drive or drive array and does nothing but read during this process (which means 0 chance of disturbing data on the array). Using an application of this nature means it is unnecessary to back up the disks as a separate step. Since you will image the array out to another source once the correct parameters are discovered. Then use a recovery program to retrieve the data. GetDataBack from RunTime also works very well.

DO NOT ATTEMPT THE FOLLOWING OPTION WITHOUT BACKING UP ALL PARTICIPATING DISKS!

Another option is to use a 'non-destructive' option on your controller to rebuild the array using the exact same parameters the original array was created with. In other words, if you used all default settings then use them again but do not initialize the drives prior to creating the array and use a skip/nit type option and not a build/verify if available on your controller. If you used a non default set of parameters to create the array like perhaps a 64k stripe when default is 256k then do that again. If you are not certain of the original parameters DO NOT USE THIS METHOD. Instead, go with Raid Reconstructor as it allows you to try different configs and even has a pretty good auto feature where the application gives the most likely settings based on the information found on the drives.
BTW: If you are not sure or don't feel comfy about trying any of this, don't! Send them to someone who has experience completing these task. Also, remember there are never an guarantees of successful data recovery.

I am here to help you to whatever extent you need. How would you like to proceed?

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