One drive down in a RAID 5 array, no biggie right?
You definitely need to SAFELY get that drive back online and reintegrated into the array.(What if it’s two drives? You better call an expert quickly)
Our Disclaimer: For the record, this is not a situation that you want to test your technical skills on. You may be on the road to catastrophic disappointment. (if your data is absolutely important or crucial please contact a professional recovery company)
FIRST…. Here’s a couple facts you should understand:
- One wrong step you will find yourself in a messy situation.
- You can cripple a professional’s chance of recovery by 50% or more.
- There is no way to recovery overwritten data.
- This can happen very easily by running free, or any kind of online software.
- Free software does not block writing back to the drive.
Recovering from a RAID 5 failure where there are failed or mechanically damaged drives involved is best left up to the pros.
I’m not being negative here, just realistic.
Most people have no idea the damage caused by:
- A simple audio inspection of a dead hard drive
- Simply putting power to the drive
- Spinning up the drive
- Using online recovery software
- Mishandling the drive
Now that the disclaimers are out of the way here, let’s take a look at some very important details to keep in mind to prevent imminent failure, and permanent data loss.
Behold the 8 deadly sins of recovering a RAID 5 array that has failed in one way or another.
WHAT TO AVOID:
1. Leaving your system on or using it to research how to fix your problem
If your RAID array has crashed or you are experiencing any symptoms other than running in tip top conditions, you want to make sure you shut it down and fix whatever is out of whack.
You could easily overwrite your data.
Leaving your RAID device on data is able to be written back to the drive as long as the power is supplied.
2. Forcing your array back online
NEVER USE THE force online function.
FIRST and foremost, you need to know WHAT is failing and WHY.
Is it a faulty:
- Power Supply?
- Back Plane?
If you force the wrong drive online you will absolutely corrupt the array.
How do you know which is the wrong drive? Great question. You need to be able to determine which one failed first, and at what time it failed.
3. Reinitializing your drive
Flat out, there isn’t even a conversation to have about this.
If you initialize your drive you will lose your data.
If your system asks you to initialize your drive, it’s because it cannot read or locate a valid partition table.
This can be for many reasons:
- Corrupt operating system
- Bad sectors on both drives
- Failing heads
- Other failing internal disk hardware
- Migration between storage controllers
- Non-standard partition configuration
The initialize command creates a new partition table with a new partition. If this happens you will absolutely need professional data recovery services to get your data back. See #8 for further details about this.
4. RUNNING Spinrite
Many people swear by Spinrite, and that it repairs hard drives that have issues. This is completely FALSE.
Spinright runs (ruins) the drive trying to remap the bad sectors.
The problem with this is it puts a tremendous amount of strain on the drive and its components. In the case of a clicking drive, Spinrite will never have any benefit or ability to repairing it.
If failing hardware caused the bad sectors, it’s only going to make it fail faster.
5. RUNNING Checkdisk
I can’t tell you how many drives we have seen and mostly heard of failing during a check disk.
DO NOT RUN CHECKDISK…
When check disk runs it looks for orphaned files and relocates them, and sometimes those orphan files are good user data.
This has the potential to corrupt the data, and even if you can recover it will be incomplete. Take a picture and rip it in two, and this is the potential result from a botched check disk.
6. Replacing more than one failed drive in RAID 5, and more than 2 in RAID 10
RAID 5 and 10 arrays are built to be able to lose one drive and still function in degraded mode. When you have a situation where 2 drives fail, and yes it happens, attempting to replace both failed drives will cause the array to rebuild incorrectly.
Replacing more than one drive in RAID 5 will cause your array to rebuild incorrectly.
After this happens, you will be forced to send both the failed and good drives to a professional recovery service to get your data back. Success rates in these situations are less than 35%.
7. Reconfiguring one RAID to another RAID configuration
DO NOT reconfigure one RAID to another
In other words…. You’re data is wiped.
8. Running free or cheap online software utilities to try to recover data that is “missing”
This is usually the first thing people try to do. For many reasons which are understood and misunderstood, but this method is like playing Russian roulette.
Running free or cheap online software can overwrite your data.
If you do not know why your data is “missing”, then you have no idea where to start looking for it. Neither does online software.
For example if the reason why your data has come up missing is faulty internal hardware, you are only exacerbating the problem.
Changed Your Mind Yet?
If you have decided that you would feel more confident to talk to someone about your recovery, and you would like to speak with an engineer, please feel free to call the number below and receive a free consultation on your case.
Discussion: Tell us about your experience with RAID 5 failure. What would you do different if it happens again? What are your feelings about RAID 5 configuration: PROS or CONS? Let us know below!