RAID 5 is a popular RAID level for data storage, seeing use in servers for businesses of all shapes and sizes. While RAID 5 is resilient and features redundant data to protect itself in case of a hard drive failure, it is not immune to failure, and a RAID 5 failure can be devastating. Loss of data, loss of revenue, and loss of customer confidence can set you back days, weeks, or even months. The consequences of RAID 5 data loss can wreak havoc on your business—if you don’t start looking for data recovery solutions on the double.
There are dozens of ways a RAID 5 server can fail. A fire, a flood, or a power surge or outage due to a lightning strike can do the trick. Acts of God notwithstanding, these arrays can also fail due to old age as the hard drives inside wear out. And, of course, you can't rule out human error.
Gillware Data Recovery has a simple, step-by-step method to recover RAID 5 data after a server crash. With our nine-step process, our RAID recovery experts have saved thousands of clients from their failed RAID 5 servers over our past decade-plus of data recovery work. Our data recovery process is 100% financially risk-free, with free inbound shipping and free evaluations. We don’t charge our clients for our work until we successfully meet their data recovery goals.
Gillware has a nine-step process to recover data from crashed RAID 5 servers and NAS devices:
Read on to learn what goes on in each step in further detail:
Because RAID 5 has single-drive fault tolerance, a RAID 5 array won’t crash, even after one hard drive has failed. However, if a second hard drive fails, the RAID array and your data become inaccessible.
The failed RAID 5 arrays we receive in our lab tend to have two or more failed hard drives. We need to image the broken hard drives, too. But before we can do that, we must fix them first. We make the necessary repairs in our Madison, Wisconsin-based data recovery lab, which features ISO 5 Class 100 cleanroom workstations and an ample library of replacement hard drive parts.
After repairing the drives, we make disk images of them as well as the healthy drives. Sometimes, if a hard drive’s hard disk platters have become scratched or scored, a 100% complete disk image isn’t possible. This is due to the destruction of physical sectors on the disks, which we cannot reverse.
Every hard drive in a RAID array has metadata placed on it to help determine its role in the array. The metadata, among other things, can tell us the last time data was written to a given drive in the array, helping us determine which failed hard drive is stale. Out of two failed hard drives in a RAID 5 array, we only need one to “fill in” the holes in the array. We avoid using the stale drive to fill in these holes whenever possible. But in some situations, in order to recover RAID 5 data, our engineers have to rebuild the RAID 5 array with the stale drive and salvage the usable data from the array.
When you need someone to recover RAID 5 data for you, now you know where it needs to go. You need to bring it to a professional data recovery lab like Gillware. But what should you do before you get in touch with us?
When your RAID 5 server crashes, the actions you take before you even start thinking about data recovery can have a huge impact on the safety of your data. Gillware has twelve handy tips for safely handling your crashed RAID 5 array:
RAID 5 uses special parity functions to reconstruct lost data if one drive fails, but cannot handle two drive failures. After one hard drive fails, the rest of the array functions normally. But as time passes, the data trapped on the failed drive becomes increasingly out-of-date. Sometimes, two or more hard drives fail almost instantaneously. But in most RAID 5 recovery cases, one of the failed drives has become stale.
RAID 5 arrays use parity calculations to provide fault tolerance if one hard drive fails. The parity data created by the array spreads out in a particular pattern throughout the drives. In order to reconstruct the failed array, we must understand exactly how this parity data has been spread out. Using the metadata on each drive, our RAID recovery engineers can determine how the array has distributed this data across the drives.
To rebuild the array, our RAID recovery technicians write customized emulation software to string the disk images together. We can then identify how the array’s storage space has been carved up into logical units. Small RAID 5 arrays will often have one logical unit spanning their entire capacity. Larger storage area networks may carve up their storage space into multiple units.
Many of the RAID 5 arrays we see here at Gillware have suffered physical damage. But we also see RAID arrays that have suffered logical damage as well (and occasionally, both). The filesystem comprises the backbone of your RAID’s logical structure, acting as a roadmap to point you to the locations of your files.
RAID 5 arrays break all of the data written to them into stripes, distributed across the array’s hard drives. If we don't put the stripes together in the right order, useful data turns into a Picasso painting (only with less value to the artistic world). By testing large files—large enough to have chunks on every drive in the array—our engineers can make we've placed the disk images in the proper order. Since this testing method works best with bitmap image files, our engineers call it “the bitmap method”.
Logical damage to a RAID 5 array can cause damage to the filesystem. This can erase the signposts pointing to some files and make them appear to have vanished. Using advanced data recovery tools of our own design, we can scan through the reconstructed RAID 5 array to pick up any files that the directory structure may have made “homeless”.
Our work to recover RAID 5 data ends with the failed RAID 5 array properly reassembled. Finally, our RAID recovery engineers pull off all available data from the array and place it on a healthy external hard drive to return to the client. Our engineers make sure that the client’s most important data is as functional as possible. If necessary, we show our client a list of recovered files to make sure we have successfully met their goals.
And if you find free data recovery software, whether for Mac or for Windows or for Linux, all the better.
But RAID recovery software isn't likely to help in really severe cases.
These products simply aren't as strong as what data recovery professionals use, especially ones you can download for free. Maybe you can recover deleted files from a healthy RAID or salvage data when two of your drives have just had a little hiccup and are otherwise healthy.
But any existing software you can find, even RAID recovery software that's really powerful, won't provide you with the skill and expertise to recover data from severely failed NAS devices and servers.
Any data recovery program or utility you get through a free download will let you work through all of these steps on your own. If the situation is truly dire, DIY data recovery utilities could even make it worse!
Keep your array safe and give Gillware's client advisors a call.
Gillware's professional data recovery lab in Madison, Wisconsin is one of the top data recovery labs in the world.
Data loss, especially when it's from a crashed RAID 5 server that's ground your business to a halt, is never an easy or painless thing to go through, but we strive to alleviate as much of the pain as possible.