iRecover on RAID 5 data recovery very slow

[oshogg]

Hi,

I had a RAID 5 array (of size 890GB) consisting of 4 320GB disks that was controlled by "Intel Matrix Storage" RAID on my motherboard. I think this is probably the biggest mistake I have ever made in configuring a PC - to rely on a chipset RAID 5.

The RAID 5 configuration got lost for some reason (read at the end of this post if you are curious how). Now, I see 4 separate disks as "Non-raid Disks". I used iRecover to create a virtual RAID 5 disk and added all the 4 disks. Thankfully, iRecover was able to recreate the virtual image for the RAID 5 and I am able to recover the data to an external 750GB hard drive. I think all the 4 disks are OK and they did not fail.

The problem is that the data recovery is extremely slow. iRecover shows 0.5 MB/sec with 2 or 3 seeks/sec. Is this normal or very slow? At this rate, it will take me 16 days to recover the 700GB of data. The read and write cache both are 512MB. I have total of 3GB RAM on the machine with iRecover as the only application running. CPU (Pentium 4 3.2GHz) usage is 5% or less. What can I do to get a speedy recovery of the data?

Thanks,
Osho

P.S.

HOW I LOST MY DATA:
----------------------

Here is a tidbit of how I lost my data. It was not because of a disk suddenly failing. Here are the sequence of events that led to RAID volume configuration getting lost.

• I got 2GB memory to upgrade my PC's 1GB memory to 3GB.
• I shut the Windows PC down normally. I opened the PC case and installed the new 2GB memory. Closed the PC case and booted.
• I got a message from Intel Matrix Storage Console software (the worst RAID software in the world IMHO) that one of the disks had failed.
• I had got similar messages with disk failing for different disks most of the time I opened the case and closed it. I usually mark the failed disk as normal and then RAID array parity is built and the array works fine for weeks or moths.
• I did the same again. I marked the failed hard drive as normal. This time, the parity build did not begin.
• I rebooted the machine. There was no parity being built. Also, all the 4 drives were reported as "Offline Members" in the initial BIOS boot screen.
• I got a message saying that I must mark the disks as not part of array in order to use it. I clicked Yes on that. Now, I realize that I should not have done that .
• After rebooting, all 4 disks are reported as Non-raid drives. Windows sees them as 4 separate disks. 2 of these disks are mounted as logical drives (D: and E:). And the other 2 are not.
• At this point, I got iRecover after some web search. Thankfully, it recreated the virtual RAID 5 array and I can retrieve data. But, it is tooo slow.
• I wonder is there any way to "force" Intel Matrix Storage Console to reconfigure these 4 disks as the RAID 5 array - considering that all the data is still intact.

Sorry for a lengthy post. But, I would really appreciate your help.

[Joep]

Hello,

How is the external disk you're writing to connected? Because I think that's where the slowness comes from.

[oshogg]

The external disk is a USB 2.0 disk. I have connnected it to a USB port on motherboard at the back of the PC. The port is supposed to be USB 2.0. However, I do get a warning from windows by a baloon message in system tray that "This device can perform faster if connected to high-speed USB port". When I click on that message - I am told that there are no high-speed USB ports available in my system even though the USB ports at the back of the motherboard are supposed to be USB 2.0 ports. Is this the root-cause of the slowness?

Thanks for your help.

Osho

[Joep]

Hello,

Yes, very likely, it is a huge bottleneck. And also, if enabled, disable the resident virus scanner for now, but remember to re-eanble it before opening any files.

[oshogg]

Thanks for the suggestion. I changed USB port setting to 2.0 in the BIOS and now the hard-drive is connected at USB 2.0 speed. The data is now being transferred at the rate of about 5MB/sec - so it is 10 times faster!!

Thanks for all your help.
Osho

[Tom]

No problem, and well done.

[oshogg]

I have recovered all the important data on an external drive now. Over 99% of files seem to have recovered just fine. But, I do see that some files have not.

Is it possible to get the original RAID 5 configuration back in such a way that I get the original RAID 5 back (see my original post for details on how I lost the data)? As far as I understand, none of the RAID 5 hard drives really malfunctioned. Just the RAID 5 configuration as understood by Intel Matrix Storage RAID is screwed up.

thanks,
Osho

[Joep]

Hello,

Well, 9 out of 10 times, in any dataloss scenario, more than 99% of the data is still intact and that's why software like iRecover is often able to recover most of it. Often the loss of access to data is caused by a few bytes or even bits in some administrative area being not what they should be.

Frustrating is, that correcting those bytes isn't often possible without the exact knowledge of the layout of the corrupt structure. And in this case I do not have that knowledge so I can not guide you or point you in the right direction to rebuild that array with tha data intact.

I am really sorry.