Recovering Data from a Single RAID-5 Drive

We had an interesting experiment recovering data from a single drive that was part of a RAID-5 array, as we are expanding our storage. The specific 4TB drive came from a Synology NAS using SHR-1, which is essentially RAID-5 with Synology’s flexibility layer on top. As we’re about to wipe & dispose the drives, we took the extra step of extracting information from the drive to see what could be done from a non-wiped drive.

Out of curiosity, we removed one of the 4TB drives from the array and connected it to my Windows PC. Normally, data on a RAID-5 array is striped across all drives with parity, so accessing usable files from just one drive shouldn’t be possible—or at least not easily.

But then we opened WinHex, a powerful hex editor and forensic tool, and started poking around. We used the simplest method: Tools – Disk Tools – File Recovery by Type. To our surprise, we were able to scan through the sectors and recover multiple .jpg files, clear enough to read their contents.

Although most data were corrupted—some were fully viewable images. Since RAID-5 stripes data in blocks, some entire files (or large portions of them) can exist intact on a single disk, especially if the files are relatively small or haven’t been fragmented across the array yet. Since our RAID’s stripe size was 64K, it means any file smaller than 64KB has a chance of being left fully intact as it can fit in a single chunk. The smaller the file is, more likely it’ll be recovered.

Key Takeaways:

• Even a single RAID-5 disk can contain (partially) readable file fragments.
• Tools like WinHex can help you (or any other bad actor) to manually extract and inspect this raw data.
• It’s not a guaranteed recovery method, but it might be just enough to salvage important files.
• You must safely wipe your disk before discarding them, even if it’s from a RAID-5 array. A simple fast-format won’t change anything.

Also, If you’re in a bad situation and have lost access to your RAID, don’t assume all is lost—some of your data might still be hiding in plain sight.