Data Recovery Weekly

As of now, there is no automatic recovery of JBOD parameters. At least, I'm not aware of any automatic software that really works. With a filesystem which stores its metadata all in one place and close to the start of the partition, like FAT or NTFS, you only get the data from the first JBOD member. All the files on the second and further members is lost. However, with a group-based filesystem, like Linux EXT-series, you can get much of the data by just feeding JBOD members to the data recovery software in turn. In group-based filesystems, metadata is spread evenly across the partition, and file contents are put close to their corresponding metadata. So, if you scan separate JBOD members and then combine the results (skipping empty files and correcting for a loss of folder tree), you can get most of the files out. You cannot recover files which have contents and metadata on two different JBOD members, and also parent-child relationships crossing the disk boundary will be lost....

After a disasterous data loss coused by the raid system I have changed all to JBOD assuming that 1/8 data loss is more acceptable than a full disaster . Wrong. If you have eight drives in JBOD, and one of them dies, there are several options: On NTFS filesystem, if first drive dies, the entire array is lost. If any other drive dies, 7/8th of the data is lost. On ext-whatever, you can salvage an unspecified amount of data because the superblocks are distributed more-or-less evenly across the volume. However, everything in disk groups which span across two disks is likely lost. So you can theoretically approach "1/8th of the data lost", but that involves using some data recovery software and is far from easy. If you want to be sure that the loss is limited to 1/8th of data in eight-disk configuration, forget JBOD and create eight separate volumes instead.