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

[how did the failure occur]

Server model: Dell POWEREDGE server

Raid level: 12x 500g hard drives make up raid5

System platform: Linux platform

File system: ext3 file system

Fault description: during the normal work, the volume was suddenly offline, and the administrator hurriedly entered the computer room to check and found that there were two hard drives with yellow lights, and the ID of these two hard drives were No. 1 and No. 4 respectively. In this case, the administrator first called Dell for after-sales consultation, and the after-sales staff suggested that customers randomly choose a hard disk to go online forcefully, so the user carried out a mandatory online operation on disk 4, but the problem became more serious. After being forced to go online, you can mount, but most directories cannot be opened, and the files in some directories have been lost for nearly 7 days. In this case, the administrator realized the seriousness of the problem and immediately chose to shut down and contact our company.

[how do we recover raid5 data]

1. First of all, our team's original raid5 structure composed of 12 hard drives is analyzed, disk 4 is removed, disk 1 is added, and the raid platform is built through virtual environment.

two。 In this step, we used a piece of software we developed independently (which is not sold to the outside world at present) to extract data. After extraction, we found that disk No. 1 had irregular bad channels.

3. We chose a commonly used mirroring tool to fully mirror the No. 1 hard disk, and more than 90% of the bad channels were read successfully.

4. Add the mirrored data to the virtual raid environment, extract the data again, and more than 99% of the data has been completely recovered.

[how long did it take]

It took us only one working day from the repair sent by the customer to the successful recovery of raid5 data, and the customer was very satisfied.

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