When your drive starts showing signs of failure, it’s time to start thinking about recovery. RAID is a great way to increase the speed of your storage, but it comes with a cost: failures. When a drive fails, the data it was storing is no longer accessible.
To recover from a failed RAID, you will need to re-strip the drive and rebuild the array from scratch. Luckily, it’s a fairly simple process, though it does require some foresight on your part.
In this blog post, we’ll explain the different stages of raid data recovery, as well as steps you can take to increase your chances of success.
Why does RAID fail?
The most common reason for a RAID to fail is a hardware failure. Hardware failures can be caused by anything from overheating, to the power supply not functioning correctly or even outside interference.
The other possibility, which is more likely in a home environment where you might turn off the computer and not think about it again for weeks, is data corruption.
This can happen when there are writing errors that occur on your hard drive. When these errors happen, it corrupts the files so they no longer make sense to the operating system and can’t be read or written to by software.
Different RAID stages
When a drive fails, the RAID may not be fully broken. This is because of how data is stored in a RAID. Data isn’t written to all disks at the same time, which means one disk may store only half of the data on a RAID volume.
If you have a two-disk configuration and one disk dies, you can write data to only the remaining disk. If you have four disks, three will contain data and one will be empty. Once you’ve determined that the drive has failed and there are no other failures in your array,
it’s time to backup your data and start recovery! If your RAID is still partially intact, then it’s possible that some files are not compromised and can be recovered without reformatting or rebuilding the entire array.
To check this before beginning recovery, boot up from your operating system installation disc or another installation disc that won’t affect your raid system (e.g., Linux Live CD).
Then try opening some files on each partition until you find the one that was corrupted by the failed drive. You may also use CHKDSK allocation units to find damaged files on partitions with complete redundancy.
RAID recovery process
The first step to recovering from a failed RAID is identifying the faulty drive and replacing it. You can use your computer’s built-in diagnostic tools, such as Disk Utility, to identify the faulty hard drive. Once you’ve replaced the drive, you need to re-strip it and rebuild the array.
- Re-striping The first thing you should do after replacing a failed RAID is re-striping it. This will remove all data on the drives and will prepare them for a new array reconstruction, which is necessary because rebuilding an array without re-stripping would cause a loss of data due to bad blocks on one or more of those drives.
- Rebuild Once you’ve completed re-stripping your RAID, it’s time to rebuild it using some backup copies of your data that you made before the failure happened. The best way to do this is with a copy of your operating system and any other software that was on that RAID when it failed (such as word processors).
- Test Run Test running your newly rebuilt RAID is an important step in order to ensure that everything went according to plan with your recovery process. If this test run fails, then there may be issues with bad blocks or other physical damage that couldn’t be detected by just looking at the disks; this could potentially lead to another failure down the line if not resolved quickly enough
What to do before RAID recovery
Before you attempt to recover a drive in your RAID, there are a few steps you should take. To start, you need to stop all access to the RAID group. This means shutting down any servers or workstations and unplugging any external drives. Next, you’ll want to back up any important data on the failed drive that is not on other disks in the array.
Finally, shut down the server and remove power from it – this will ensure no one accidentally attempts to access the drive before beginning recovery. Once you have these steps completed, it’s time to start recovering your data. The first step of recovery is rebuilding the array from scratch; this is done by discarding all information on your RAID drives and replacing them with new ones.
Once your hard drives have been replaced with blank disks, you can proceed with re-striping them into an array and restoring data from backup discs onto it.
What to do during RAID recovery
There are three steps to follow during RAID recovery: – Striping the failed array and rebuilding it from scratch with your spare disks – Manually copying data from the new array back over to the old one – Restoring data on the old array back to the new.
While RAID is a great way to increase the speed of your storage, it comes with a cost: failures. When a drive fails, the data it was storing is no longer accessible. The good news is that these failures are completely preventable! To recover from a failed RAID, you will need to re-strip the drive and rebuild the array from scratch.