Shulou(Shulou.com)06/02 Report--

[description of data recovery failure]

A linux website server, DELL R200, manages about 50 websites and uses a SATA 160GB hard drive. There was a sudden downtime in normal use, and the attempt to boot failed again. When the hard drive was removed and tested, it was found that there were about 100 bad sectors.

After a data recovery company repaired the bad road, it tried for about 3 days, but failed to recover.

[extrapolation of the cause of data recovery failure]

The cause of the failure of data recovery is often not clearly known, and in this case it is only inferred as follows:

1. After a bad road occurs, the user may try to carry out automatic or manual fsck operation, resulting in further disaster.

2. If some of the block groups are all 0, it is possible to have done unfinished mkfs.

3. The data recovery company sent for repair is not professional and has the possibility of destroying the data.

[data recovery process]

First of all, the fault disk is mirrored completely by PC3K with DE, and the data is analyzed in the mirror. The whole hard disk consists of two partitions: 100m boot partition and / partition of the remaining space (managed by LVM). The file system is EXT3. The root partition super block is normal, according to the super block view the first block group description table is normal, but the node area is all 0.

According to the analysis of other block groups according to the block group description table, it is found that the first 27 block groups are all 0, but there is obvious user data in the data area before and after the block group. The metadata of the middle block group is normal (description table, node, BITMAP, etc.), and the metadata area of the last part of the block group is all 0.

Try to find the root directory and restore the root node area with the root directory as a clue.

Generate the file system tree with the generated root directory node area and root directory records. After success, you can already see a large amount of data, and the file system structure is normal. However, the node of some files or folders is 0, and through node tracking, it is found that the node area is located in the front and back part of the file system.

An attempt was made to restore files and folders with node area 0. Most of the folders were restored successfully, but most of the files could not be restored.

An attempt was made to restore the .TAR.GZ backup package made by the user, but it was successfully restored, but an error occurred when it was opened, the intermediate data was destroyed, and only a limited part of the website could be exported.

Finally, the data is recovered successfully.

[suggestions to users]

1. Important data must not be stored in a single disk. At present, it does not take a lot of investment to construct a simple RAID.

2, be sure to do a good backup work, at the very least, the backup package should not be placed on the same storage, second to none, and must not be placed under the same partition.

3. After the failure of the hard disk, do not try to deal with it again and again, but should do a full backup operation as soon as possible.

4. Choose a professional data recovery company to deal with as much as possible, and unprofessional companies or individuals will destroy the failure disk unintentionally or intentionally (the intentional purpose is to improve the blackmail of quotation or maintain the reputation).

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.