Years ago, I downloaded some videos that have since become corrupted, and the original copies are no longer available online. I'm wondering whether it's possible to partition a phone's SD card—or use some kind of software RAID—to create a redundant array such as RAID 5. Would RAID 5 have protected the videos from corruption, and are there any practical ways to diagnose or repair the damaged files?
3 Answers
Whether a video can be repaired depends on the damage. First make a copy of the original and work only on the copy. Check whether the file has a normal size and whether media players or tools such as FFmpeg can read any streams from it. Sometimes rebuilding or remuxing the container helps if only the metadata is damaged, but if the actual video data is missing or overwritten, it usually can’t be recovered without another copy.
A phone generally can’t provide a practical RAID 5 setup. RAID 5 needs at least three separate storage devices, not just partitions on one SD card, because partitions on the same physical card all fail together if the card dies. Most phones also lack the hardware connections and software support needed to manage multiple independent drives. Software RAID exists, but using it on a phone would be cumbersome and could add processing and battery costs.
RAID 5 would mainly protect against one storage device failing, not against every kind of file corruption. If bad data were accidentally written and the array synchronized it, the corrupted version could be preserved across the redundancy information too. It also wouldn’t protect against accidental deletion, malware, filesystem damage, or multiple device failures. Separate backups are much better for preserving irreplaceable videos.
Exactly—RAID can improve availability, but it isn’t a backup. For important files, keep multiple independent copies, preferably on different types of storage and in different locations.
Software RAID is technically possible in some environments, but partitioning one physical card doesn’t provide meaningful redundancy. You would need multiple independent devices for RAID to protect against a drive failure.