Failure on an installation of hard disks mounted in Raid, what to do?

Failure on an installation of hard disks mounted in Raid, what to do? For those new to RAID (Redundant Array of Inexpensive Disks), it is an installation of hard drives that stores data on multiple hard drives simultaneously.

There are different types of RAID with very different levels of data redundancy managed. Raid 1 and Raid 5 are the best known. Each Raid system has its pros and cons.

This provides some fault tolerance since the data is copied multiple times, or can improve performance (read and, or write) depending on the type of Raid installation chosen. Like any hardware, even a raid 5 in a server or NAS can fail at different levels (hardware or software).

The problem is that a Raid installation often contains important data. This is not the kind of computer installation that one sets up for fun. It will often be necessary to go through a specialized laboratory if you want to recover the data on this type of installation.

What if your Raid installation fails?

Try to identify the fault

Don’t take any raid failure lightly. Some configurations are so complex that mishandling could seriously aggravate the situation of losing your data.

Most manufacturers, like Dell for example, have web pages that can help you understand and troubleshoot hard drive and Raid issues. If you do not have the skills in-house, do not hesitate to use a specialized company.

If the failure seems to come from a hard drive

Choosing the Right Replacement Drive

If it is a faulty hard drive, try replacing it with a disk ideally of the same model. Check via the “Part Number” on the manufacturer’s label. If you do not have an identical model, opt for a disk that is at least the size of the failed disk.

Please note, as a reminder, two disk models sold with the same amount of storage space (1,2,4,6,8 TB) do not necessarily have the same usable size once installed and formatted. In other words, a 2TB drive from Brand A might offer less space than a 2TB drive from Brand B.

Hot-swapping or cold swapping?

Some Raid installations allow you to hot-swap a hard drive (= installation powered on and running) but this is not systematic. If you are unsure of this feature, it is best to shut down your system before replacing the hard drive.

On restarting, if the hard drive contains at least as much free space as the out-of-order drive, it will be possible to start rebuilding your Raid. There is also a risk at this stage because the reconstruction will take several hours. If another technical problem were to arise during the reconstruction, this would not help the situation.

Can you try to recover the data yourself?

Given the complexity of a Raid installation, trying to “tweak” its installation or any Raid recovery software to recover its data is more than risky, even dangerous for the durability of your data.

The solution of going through specialized data recovery laboratories is often the best choice.

How to choose the right service provider to restore your files?

In France, there are about ten reputable companies in this field. Not all of them are specialized, equipped, or trained for Raid restoration. This is the first point that may allow you to sort it out. There are also customer reviews but you still have to be able to identify reviews from customers who have suffered a breakdown on a Raid system because it is quite specific.

Then there is price transparency, which is not always the case. Also, these laboratories offer to send your discs for analysis and cost evaluation. Some of them even refuse discs that have already passed through the hands of another laboratory.

Find out before sending the procedure and its cost to recover your discs if it does not suit you. Avoid answers by telephone and ask for an email in order to keep writing to prevent any litigation.

Finally, these specialized companies sometimes only have a commercial center in France where they receive the hard drives which are then re-shipped to another country: where there is a laboratory. This is to know because some people do not appreciate knowing that their data is leaving the territory (not to mention the additional risks linked to transport)

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