Having a RAID fail can be pretty overwhelming, especially as the realization of its consequences in terms of potential lost data, time, and possibly even revenue begin to creep in. However in the wake of all that it is important that you keep a cool head, because the actions that you take will directly affect whether or not data recovery is an option.
In particular, here are several steps that you should consider taking:
- Shut down the system
The first step you’ll normally want to take is to shut down your system. Assuming your RAID has failed that means that enough of its hard drives (normally 2 or more) have probably failed, and if your system continues to run it may perform write data onto other drives and make things worse.
- Find out the cause of the RAID failure
Although in most cases RAID failures are triggered when several hard drives in the RAID fail, there are other potential causes as well such as an issue with the RAID controller. Based on information from the RAID controller you may be able to find out what the cause of the RAID failure is, and take action accordingly.
- Check all the hard drives
Before you even think about fixing the raid, you should check each hard drive individually. The idea is to identify failed hard drives, and figure out which ones have failed. If you’re lucky, perhaps only one hard drive has failed in which case you technically should be able to recover everything.
- Figure out whether a rebuild will help – or not
One of the common ways to recover data is to rebuild the RAID – but that isn’t always a good idea. The only way in which a rebuild can help is if all the data is accessible and functioning well, and if the hard drive that has failed has been replaced. In situations where more than one hard drive has failed then that criteria is unlikely to be met – in which case a rebuild could make things worse.
- Get professional help
Assuming you aren’t an expert and don’t have experience in RAID recovery – it is important that you don’t make an attempt to do so. That may sound counterintuitive, but the fact of the matter is that any misstep (however small) could lead to a permanent and irreversible loss of data. In short if you aren’t entirely sure about what caused the RAID failure and how to go about recovering data – you should get an expert onboard to help.
- Make an image of the storage array
In the event that you do happen to know how to recover data from a RAID – you should still make an image of the contents of all the hard disks in the storage array. Consider this a backup that you can potentially use to recover data if your initial efforts fail and the data on the actual drives is lost permanently.
As you can see having a RAID fail doesn’t necessarily mean that all your data is lost – at least not yet. By taking the steps listed above you can maximize your chances of recovering as much data as possible, or at very least give an expert a good chance of being able to do so.
