SSD RAID0-software recovery issue
 

Hi folks,

I'm trying to recover some contents (text files) from a RAID0 SSD units mounted in a video and metadata recorder (Vantage PSU-3). These devices are used by video-assistants in TV/cinema shootings, and record video feeds and data entered by the user. By accident, the unit was formatted before downloading its contents. The unit system uses some flavor of a linux system.

I've extracted the disks and mounted the RAID under Ubuntu (autodetected by md). Obviously, the directories where the data should appear are empty. I've tried testdisk, gparted and several tools with no luck. I've tried to contact the manufacturer to find out if the SSD are low-level flashed when formatted. The data should be there provided that the unit don't use TRIM operations, right (these are aimed at general OSes, correct me if I'm wrong).

By the moment, I'm copying with dd its raw contents to another unit. Each disk is 800GB.

Anyone know how to make a recover aimed to a certain file type (text, pdf, etc) under GNU/Linux?

Thanks in advance for your valued suggestions.
Jordi

I suspect that the device records the video as just binary or "raw data" so testdisk and photorec might not work. Without knowing how the recorder works I would be reluctant to suggest anything. Copying the data is good and hopefully the manufacture will respond with a method to recover your lost video.

SSD drives work differently from ordinary hard drives. When the drives/array was reformatted, the OS probably sent a huge number of "trim" commmands to both drives, telling them that all the sectors previously allocated to various files are no longer in use.

That means the drive can ignore the contents of those sectors when another sector in the same erase block has to be rewritten, which increases performance, but it also means the drive may choose to return a fake response containing only zeroes to any read request for those sectors.

Some drives do this, others don't; it all depends on the firmware. If you can't find any data using tools like TestDisk or PhotoRec, that indicates pretty strongly that only zeros are being returned. If so, the dd operation is likely to result in an almost completely blank destination disk.

You could try reading a few random sectors from the beginning of the array with dd (or read directly from one of the array members with hdparm); you should not have to try many sectors before seeing random data. If you keep getting sectors that are all zeroed-out, you will need to contact the drive manufacturer for further advice.

It is the case with these Intel SSD S3500 series, fake response containing zeroes.

Thanks for your help.