RAID 5 Array with 2 faulty Drives

[daRecoM]

Good day,

RAID 5 array, 5 SAS hard drives. 2 out of 5 hard drives showed 'offline' in RAID utility.
We have checked all hard drives and below are the results

HDD# 0: Healthy
HDD# 1: Detected with correct size and model, running slow at certain blocks during imaging process
HDD# 2: Healthy
HDD# 3: Imaging process stopped/ hung half way. Size and model still detectable
HDD# 4: Healthy

Data recovery after rebuilding RAID array is not possible simply because the file system is not supported by almost all commercial recovery software.

Now we are thinking of making a clone copy of HDD# 1 to a brand new SAS hard drive (same capacity & brand), and insert HDD# 0, HDD# 1, HDD# 2, HDD# 4 back to the server

Question

1. Will the RAID controller detect the cloned unit as a new array member and fire up RAID rebuild by itself?

2. In the event of RAID controller show all 4 hard drives status as 'Online", that should be good enough for us to bootup the operating system, right?

Please advise and thanks in advance.

[mr_spokk]

Clone each drive, and then work with the clones....never directly on original drives.

Bosse

[day1data]

Like mr_spokk said don't work with the orignal drives. Only work with clones of each drive.

1. Will the RAID controller detect the cloned unit as a new array member and fire up RAID rebuild by itself?

The RAID controller will probably detect the new drive as not initialized and not part of any array. Mainly because the new drives serial number will not match the original drive.

2. In the event of RAID controller show all 4 hard drives status as 'Online", that should be good enough for us to bootup the operating system, right?

The RAID should run in degraded mode but that requires all 4 drives to be working at 100% or the RAID will crash immediately.

[labtech]

What cloning tool is used? Professional hardware/software will likely yield much better results.

[lcoughey]

What is the file system?

[drHDD]

Advise is to clone all drives and rebuild raid in R-studio or similar software. Playing with controller and original drives it's kind of dangerous.

[data-medics]

Just a few things before I even attempt to answer your two questions. First off, what is the filesystem type that you say isn't supported? Also, are you certain that both of the failed drives failed at exactly the same time? Most often I find that one has been offline for months and is terribly out of sync with the rest of the set. That having been said. To try and answer your questions:

1. Not likely. Most hardware RAID controllers will check the serial number of the drive and if it doesn't match they aren't going to attempt to use it. Only a Linux RAID which relies entirely on metadata can you usually get away with just imaging and plugging it in.

2. Yes, but only if they are the correct 4 drives. If one is out of sync from being offline for some time, it'll almost certainly fail to boot.

In any event, as was already pointed out several times, using the original controller to try and rebuild is dangerous and shouldn't be attempted. If you don't have the skills to rebuild the array using the clones and software, enlist the help of someone who does have the skills. Perhaps they can do it remotely, and you might even learn something along the way.